How to Calculate Your Ovulation

Updated on April 19, 2016

How Do I Know When I'm Ovulating?

Ovulation is the phase in a woman's menstrual cycle when an unfertilized egg is released from the ovary and travels through the fallopian tubes and into the uterus. This is the stage of the menstrual cycle during which pregnancy can occur, if the released egg is fertilized by sperm.

This Hub will explain how to use the length of your menstrual cycle to determine when you may be ovulating. It also explains other ways of predicting and detecting ovulation such as tracking your basal body temperature, cervical mucus, or purchasing an ovulation kit.

An egg moves from the ovaries, through the fallopian tubes, and implants itself on the uterine wall.
An egg moves from the ovaries, through the fallopian tubes, and implants itself on the uterine wall.

Step 1: Calculate the Length of Your Menstrual Cycle

You should make a note of when your next period starts. This is the first day of your cycle. Then, make note when your period comes again, in the following month. This is the beginning of the next cycle.

When you count the days in between, this gives you the length of your cycle. You might want to do this for more than one month, as menstrual cycles can vary in length from month to month. This will also help you determine if you have an irregular cycle, in which you may skip periods for a month or more at a time. An irregular cycle will make predicting ovulation more difficult.

Here's an example:

  • Period starts: 1 January
  • Next period starts: 3 February
  • Days in between (including 1 January but not 3 February): 33 days.

The menstrual cycle length, therefore, is 33.

Step 2: Figure Out When You're Ovulating

Use the chart below to determine when you're most likely to be ovulating, based on the length of your menstrual cycle. Find the length of your cycle in the left-hand column, and determine how many days after the beginning of your period you are ovulating, and when you're at your most fertile.

Cycle Length (Days)
Ovulation Occurs
Most Fertile Days
22
Day 8
Days 7-9
23
Day 9
Days 8-10
24
Day 10
Days 9-11
25
Day 11
Days 10-12
26
Day 12
Days 11-13
27
Day 13
Days 12-14
28
Day 14
Days 13-15
29
Day 15
Days 14-16
30
Day 16
Days 15-17
31
Day 17
Days 16-18
32
Day 18
Days 17-19
33
Day 19
Days 18-20
34
Day 20
Days 19-21
35
Day 21
Days 20-22
36
Day 22
Days 21-23
A sample ovulation calendar, calculated using the table above.
A sample ovulation calendar, calculated using the table above.

Step 3: Determine Your Most Fertile Days

Use the same chart above to calculate the days of your cycle when you're most likely to conceive.

In the example below:

  • Cycle length: 33
  • First day of most recent period: 3 February
  • Ovulation is 19 days after 3 February: 22 February
  • Most fertile days are between 18 and 20 days after 3 February: 21-23 February

As a general rule, you are most fertile the day before, during, and the day after ovulation. That said, because sperm can survive for up to seven days in the right conditions, you could be fertile before and after these days. Also, research indicates that it is possible for some women with irregular cycles to ovulate during their period, though this is uncommon.

Other Ways to Detect or Predict Ovulation

  1. Basal Body Temperature: Your basal body temperature (BBT) is your lowest temperature in a given 24-hour period, most likely early in the morning when you first wake up. Two or three days after you ovulate, your BBT should rise about 0.4 to 1.0 degrees Fahrenheit due to hormonal changes, and stay that high during your period. Only tracking your BBT for one month will not help you predict ovulation, as the temperature rise occurs after the fertile window. But by tracking your BBT over several months you can see patterns in your hormonal fluctuations, and then predict when you may be ovulating.
  2. Monitoring Cervical Mucus: The consistency and color of vaginal discharge will change over the course of a month, due to hormonal fluctuations. Since one component of this discharge is cervical mucus, it can give some indication of where you are in your cycle. Right before ovulation, your vaginal discharge will become clear and develop the consistency of a raw egg white. The last day you see mucus of this consistency is the day before or day of ovulation, when you're most fertile.
  3. Ovulation Kit: An ovulation kit can be easily purchased and used to test your urine for elevated levels of luteinizing hormone just before ovulation. Ovulation kits can accurately predict ovulation 12 to 36 hours ahead of time, and unlike other methods, can predict ovulation during the first month of using them.

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    • profile image

      Minnie 2 weeks ago

      I need so much help please

    • profile image

      Anonymous 4 weeks ago

      Its 34days now since my last period and i still did not get my period fir the new month

    • profile image

      habibzenaida01 2 months ago

      i had my cycle last 19 september 2017

      im irregular period when is my evolation when i have the best sex

    • profile image

      Madeleine 3 months ago

      I had a 27 day cycle,but did it on the 20 but since that I had no period,I'm 49 years of age,could it be that I'm pregnant

    • profile image

      Alecia 3 months ago

      My last cycle was on the 15 of july and ends on the 19 of july when am I supposed to expect my other cycle in August?

    • profile image

      Patricia 3 months ago

      I got my period on the 29 of July and the dates are puzzling me Idk wen is it coming can somebody tell me

    • profile image

      Rhoda 3 months ago

      my last period was on the 2nd of August, when am i expected to conceive?

    • profile image

      May 3 months ago

      Got my periods on 23rd August, when I'm i expected to conceive???

    • profile image

      Ola 3 months ago

      I had my period 26 of July and am suppose to see it 23 of August but it came 22 of August is these normal or not these is d second time this will happen. And have been trying to conceive over six month now. Please help

    • profile image

      Angelina 3 months ago

      I have sex three days after my ovulation and I was suppose to mensurate on 21 of this month but it didn't come am I pregnant

    • profile image

      alberta 3 months ago

      i had myb period on the 21th august for 2 days, i am 22 length days, when is my ovelation period

    • profile image

      Portia 3 months ago

      I had my period on 8August pls wen will l have my period next month

    • profile image

      Mary 3 months ago

      Please I saw my last period on the 17 of August 2017 when am I seen my next period

    • profile image

      Gcinah 3 months ago

      Hi,I had my periods on the 19th of July n had sex with my boyfriend on the 26th of July so today I went to clinic n tested PT 3 times and all they were positive..so im worried now ,Am i really pregnant!?

    • profile image

      Moboaji 4 months ago

      I do see my period on the 15th of every month how to I calculate my next period. Thank you

    • profile image

      Anastasia12 4 months ago

      Hello, I have my irregular menstruation and usually it starts at day 7 of each month I had sex on day 2, and still don't have my period, am I pregnant?

    • profile image

      Aloysia 4 months ago

      Pls my last period was 29 of July 2017and end 31 of July when will be my ovulation period

    • profile image

      me 4 months ago

      Had baby 17/6/17 and I haven't had a period since what do I do x

    • profile image

      Mzmavis 4 months ago

      I had my menstruation 5th july and had unprotected sex on 2 August. Will I be pregnant

    • profile image

      LaSondra Bradford 4 months ago

      I usually start my period on the 2 of each month but here in July it started a day late on the 3and it stopped on the 6 if July I had sex that morning now here it's is the 31 of July I started on the 30 of July light then heavy light reddish then real light pinkish with slightly cramping then had sex on the 13 of July I need help determine what is going on with my body my cycle doesn't supposed to start until the 2 of August

    • profile image

      Collywear! 4 months ago

      I Missed My Periods From June 2017 Until Now... I Use To Menstruate From The 12th Every Month , So When Do I Start To Count My Pregnant Weeks?

    • profile image

      Nancy musangi 4 months ago

      Its very educative.... As for me have learned a lot...have been having menstruation at 28 last month it came 27 today has come on 25 any problem with me..

    • profile image

      my name is praise 5 months ago

      I saw my period on 26 of May and on 19 of June 2017 when am I likely to ovulate

    • profile image

      victoria 6 months ago

      plz help me calculate I saw my period on may 12 so when will I supposed to see it on June?

    • profile image

      kelechi 6 months ago

      my period is on 12/5/2017,and I see it on 6 /6/2017,which date is my ovulation, is it last 3 or 4day

    • profile image

      MissAguirre 7 months ago

      Hello my lmp was sep212016 n I had sex with guy1 sep27 but he didn't Cum in me we didn't use protection tho but I had sex oct1 to oct5 with guy2 n I was wondering when did I get i get pregnant n who's most likely the dad my due date is June 28 2017? Im thinking guy 2 since he cum in me from oct 1 to oct 5

    • profile image

      sonia90rani@gmail.com 10 months ago

      Hii m 27 years old . My last period was

      25 jan 2017

      23 dec 2016

      21 nov 2016

      19 oct 2016

      I want to know about my ovulation day

    • profile image

      Rose 2 years ago

      I had period 4th and I had six 25th will I get pregnant?

    • profile image

      great 2 years ago

      I have my period 20 September after finish my period 26 september I have sex with my boyfriend my menstrual cycle length is 30 days cycle I will get pregnant or no now I am scary please reply to me.

    • profile image

      sushmitha 2 years ago

      my mensutral cycle length is 33days...on got my period on 29th september...next month which day i will ovulate pleasee tel mee.....

    • profile image

      taundi 2 years ago

      I had sex on the 6th day after my period,is there any chance to fall preg

    • profile image

      Bukky 2 years ago

      My last period was 15/3 when is my ovulation period

    • profile image

      Nneoma 2 years ago

      I saw my period on the 21st of February, when is my ovulation and when will i see my period of March

    • profile image

      Hi 2 years ago

      Hello

    • profile image

      susan akol 2 years ago

      My period starts on 15 march, so when should i ovulate ?

    • profile image

      Lucia Williams 2 years ago

      My cycle come February the 21 when off February the 24 or 25 I had sex on March 7and the 8

    • profile image

      margaret 2 years ago

      my period was on the 20th janury nd ended 24th jan..when is the best time for me to get pregnant

    • profile image

      Sharika 3 years ago

      My period was 12-10-14 but it was suppose to come on 12-13-14 so when will b the best time for me to get pregnant

    • profile image

      Andrea stewart 3 years ago

      My period was on 22 /10/2014 i have 28 days cycle my period was due on 18/11/2014 not come on yet done preg test its negative result. Wat shall i do

    • profile image

      Lisa.M.B 3 years ago

      I saw my period 18-23rd of september 2014. And I actually think I concieved, but on the 10th of oct I saw a little blood inform of mulcus I think bcs of the drug I took doxycyclin which the DR asked me to take due to some pain down my lower right abdomen, then thru out that month, I didn't see my period and we tot I was pregnant, when I did urinary test there was nothing, so, I visited the hospital again on the 3rd of November the DR checked me and saw I was very ok and said if by two weeks I dint see it I should do blood test bcs the blood test I did on that 3rd of Nov too proved negative. When I got back home at night the period started and it ended last week on the 8th. Pls when am I likely to Ovulate and take in, as this is two months after my wedding. We are quite eager to tell u the truth. Thankz.

    • profile image

      shugnance 3 years ago

      my cycles are 24 days when would I ovulate I was on my period last Wednesday

    • profile image

      iremide 3 years ago

      My last period was on 13-15 of steptmber. Last month oct cycly length was 28 and steptember length was 29. And I had sex from 19 to 25. Can I be pregnant. Pls email me @ (boselawani@rockemail.com) thanks

    • profile image

      mercy 3 years ago

      my last period was on the 21st of Sept. and ended on the 25th of Sept. pls how can i determine my ovulation period.

    • profile image

      sri 3 years ago

      Hi my last periods was in July 16 n in that month my husband was in abroad, actually he started by July 14 th.. He returned on Aug 8 n we were together tat Nite..

      I didn't get my periods in the month of aug .. Later I was found tat I'm pregnant.. I'm totally confused abt this cyclen process. Pls do help me.

    • profile image

      love24 3 years ago

      My last period was September 5th. And I have a 30 day cycle!! When should I ovulate?

    • profile image

      esther arkorful 3 years ago

      I had an arbortion n since then am experiencn menstrual disorders because of dat I was not able to conceive pls help me

    • profile image

      Anna 3 years ago

      My first period: 27 may

      Time taken : 7days

      Next first period: 12 July

      Time taken :5 days

      Cycle length: 45

      So please help me I don't understand it at all but im normal, and can you please tell me that I have most fertile days

    • profile image

      ABC 3 years ago

      How to calculate the ovulation day

      Few dates of last periods:

      Apr 29

      June 18

      July 31

      Pls help me to calculate

    • profile image

      dev 3 years ago

      My last July periods was on july 12th and after ie it got over by 19th or 20th of July and then we had sex on 21st july but sperm didn't cum as we didn't have sex like ie.... and then we had sex on 29th and 30th of July and sperm came but with ie time we took out the penis and sperm came out and it didn't go inside... so can you tell me when is the next period date for me because I don't want to become pregnant as of now.... is there any chance of becoming pregnant?? :( could you plss mail me the details when will be next period date and when is the safe period and all ie to dazzlingtriozz@gmail.com

    • profile image

      Jacqueline 3 years ago

      Hi. The 1st day of my last period was July 23, 2014. Can u calculate my best dates of getting pregnant? Thank you.

    • profile image

      drea 3 years ago

      hi! my cycles are 33 days. I've been taking the clear blue ferililty and for 5 days I've had my blinky smiley face and haven't ovulated yet. how long are you normally in your "high" fertile days? really want to have a boy first also! HELP!!

    • profile image

      val 3 years ago

      I'm having trouble determining my cycle length could u help me my last day of my monthly was August 2, 2014

    • profile image

      monyuett 3 years ago

      i got my period april 21 to april 27 i didn't get one at all in may i got it june 2 to june 6 i started spotting june 29 it lasted on and off til july 7 then i got my period july 24 to july 28 and my pregnancy test have been negative but i feel pregnant what's going on

    • profile image

      Lynsey 3 years ago

      First day of last period 19th July 2014

      I have a 34 day cycle

      When is best to try and conceive?

      I've had a lap n dye I've had ovulation tests I'm perfectly normal a is fine. My partner is fine too. Were trying to conceive baby number 5 weve never had any problems before. Usually i conceive 3-4 months off the pill just or this time. Please can you help

    • profile image

      chisom 3 years ago

      I see my period came out June 25 and now it come out on 21 July when will I see my ovulation

    • profile image

      jay 3 years ago

      Okay my periods are 17-24th then 18th-24 then 17-22 "which was a 6 day period" had sex 4 days straight after that. What's the chances I'm Preg"? I don't want to be. What days was I obvioulating? And also how many days is cycle interval? *as in how many days is mine* if you could email/text me at conneramber75@yahoo.com/864-504-2454 that would be awesome. Thanks

    • profile image

      vuyelwa 3 years ago

      I used to get my period.1and till the 6but this month i did get my period i m on the 31 days please need help

    • Ekeh Chinyere profile image

      Ekeh Chinyere 3 years ago from Abuja, Nigeria

      I saw my period on 18 May and ended on 20th of May. 18th June i saw it and it also ended 20th June and i had unprotected sex on 22 June .

      1) when is my fertile days?

      2) can i get pregnant for having unprotected sex two days after my period?

      thanks....

    • profile image

      gift 3 years ago

      I saw my period came on 23 may. And now it come out on 22nd june pls when is my ovulation day go to be be4 I use to have a 28 cycle is 31 days I understand my body again pls I need help i nd husband we a baby pls help

    • profile image

      Helen Gumbs 3 years ago

      I want to know when my next period is due.

      katherinelwebster@hotmail.com

    • profile image

      tracy 3 years ago

      my period is same date every month that is every 7th of each month. is it normal

    • profile image

      katrina thomas 3 years ago

      I just started my period june 9th 2014 when do I ovulate

    • profile image

      L.Y 3 years ago

      i want to know ovulation start is it when included during meci period or after meci period i finsh my meci period on 31may started 27may.pls tel me wen is d ovulation startd

    • profile image

      floo 3 years ago

      I had my periods on the 13 to the 17 please help me calculate my ovulation dates

    • profile image

      Nallely 3 years ago

      If i started my period on the 24th when do i start ovulating?

    • profile image

      Shiny 3 years ago

      O.o

      You all need to have 2 periods to measure your cycle length.

      Then count the days between them.

      Look at the ovulation days for those number of days.

    • profile image

      mitchell 3 years ago

      ddear writer,pls like you said :27 ovulation is day 12-14 will count 14 day after mesuration or count from the day 1 of mesuration.thanks

    • profile image

      jeannie 3 years ago

      My last period was april 29 and know is may 21 i had unprotecred sex on the 18 and the 20 cnt i get pregnant

    • profile image

      Halima 3 years ago

      My last period ws april 9 and now may 13th what is my length and how do i know my next ovulation.

    • profile image

      Cassandra 3 years ago

      Had sex2wks before period Had period April 20th end 26,7days nbut I had sex 4 days I ovulated n had sex on May 3rd,so could I be pregnant,my cycle 29days n I ovulation day 33,can u help me out...

    • profile image

      vera 3 years ago

      My period for april starts 28 to 2 may .pls when is my ovulation.

    • profile image

      KayMarie 3 years ago

      I just need a lil help here so i can understand my cycle and ovulation a lil more cuz every site i look on theres something different... i have a regular 28 day cycle my last AF was on April 17 and i had sex on the 24 about 4 in the morning and my first fertile day is today can i still be pregnant?? Im trying to concieve since me and my husband really want another baby because hes awfully working alot i have to time my cycle and ovulation we are still going to try and have sex through out the course of the rest of my fertile days if hes not to tired i just wanted to know what are my chances of being pregnant with just that 1 day we had sex which was the 24th of April and my 1st fertile day is today the 26th of April ??

    • profile image

      raymac221169@yahoo.de 3 years ago

      Am really sad,tot i was pregnant wen i saw a small drop 9t which became clotted blood,went to hosp.and it was negativ.found bladder infection.Please,pls kindly help me calculate my next ovulation date. Jan flow was 7,February-4 March-9t and 9th,still seeing

    • profile image

      JOY 3 years ago

      i have my last period on the 25th of march and ended on the 30th of march can you tell me when will my ovulation will start.

    • profile image

      Benedicta 3 years ago

      i have my period on the 15th of march and ended on the 21th of march. can you tell me when will my ovulation will start, because i want to get pregnant. tnx

    • profile image

      jimyjimy singh 3 years ago

      My last period comes on 6 march 2014 and I had entercource on 22 march can I get pregnant or not

    • profile image

      linda 3 years ago

      My cycle changes from 32 to 34 days so i never know when most fertile time is and when i should start using my ovualtion kit

    • profile image

      kiara 3 years ago

      Hi, this is all very confusing to me, I'm 22 years old and am really trying to understand my body more and how it works.. my cycle is 30 days long, and I usually get my period on the 25th of each month. When am I ovulating?

    • profile image

      kem 3 years ago

      I am normally regular with my period. I think its a 28 day cycle. However I had my period on the 11 February and again on the 22 March 2014. That's 39 days. I was so convinced I was pregnant. Please calculate when will be the best time in this month to fall pregnant. Thanks

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      Harriet 3 years ago

      On 5th- 03- 2014 i began my periods, and it lasted for Seven days, so i want to know if anyone can help me to Know when is my Ovulation time.

    • profile image

      gwambelupe 3 years ago

      In january 27th I received my periods then 17feb I received my next when am I going to receive in March

    • profile image

      kappa gamma 3 years ago

      My period started 3/11\14 thru 3/15/14 i last 5 days no more no less so when do i ovulate and my next period from my period tracker says my period will come 4/6/14 can you please let me know also febuary period was 2/12/14 thru 2/16/14

    • profile image

      kgomotso 3 years ago

      my last period ws on the 12/02/2014 and my next one started on the 9/03/2014

      calculate my most fertile day pls

    • profile image

      Telema 3 years ago

      Pls help me calculate my fertile days,

      My last period was 06/February / 2014 and the present one is 11/march/ 2014

    • profile image

      Temmy 3 years ago

      Hi,my last period date was 19th of February,please help me calculate,tnkx

    • profile image

      Anne 3 years ago

      Hi, I want to seek your help in calculating my ovulation period. Last month February 25th ,2014

    • profile image

      Omot 3 years ago

      Useful tips there..

      Please my cycle is no regular. January this year I had my period on the 2nd Jan 2014, another one came 22nd Jan 2014 which is (21 days) the next one came march 4th 2014 which is (42 days). How then do i calculate my fertile period with this kind of condition? Please help. Thanks

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      Nikki 3 years ago

      My last period was the 3rd of feb 14 for 4 days and me and my husband trying for a baby. I mostly have a 28 day cycle. My next period should be due the 3rd much. I've been feeling tired a lot and sore boobs sometimes. Can I be preg. I have intercourse on 10th,11,13,14,16,17th feb is it possible and when could I take a test wb

    • profile image

      nams 3 years ago

      My cycle is of 39 days. Please tell me the ovulation days??

    • profile image

      joy Akure 3 years ago

      I had my period on the 19th of feb.2014,and I hav 25 circle length,when is the best time to have sex so that I can conceive?

    • profile image

      BM 3 years ago

      My cycle this time is 39 days.please tell me my ovulation day. Email id is bumoni.ozah@gmail.com

    • profile image

      funke 3 years ago

      I menstruated on d 25of dec last month wic lasted 4 5days,had another one jan22 to 26of jan 2014now and menstruating 4 feb 21of dis month wic will be off by 25th of d month.now my question is dat wen can I ve sex cos I need to conceive and dnt no ow to calculate it pls I need reply of dis soon

    • profile image

      Tia 3 years ago

      I had my period on the 20 january till the 25 january and had uprotected sex on the 28 same month and unprotected sex on the 6,7,8,9 of february todai is the 20 and still haven't received my period is it possible that i am pregnant??? Please help..

      Reply at tiamora123@gmail.com

    • profile image

      rachael 3 years ago

      Hi Just want some advice on when I ovulate. I had an ectopic pregnancy in November first cycle was dec04-07 cycle 26 days. Period Dec 30-6 Jan cycle days 27 then Jan 30-feb02 cycle days 31 .??? Please help

    • profile image

      Debra 3 years ago

      My period came on the first of january last for 5 days came back on the 22nd last for 7 days wen I qill ovulate

    • Benjamin Oluebube profile image

      Benjamin Oluebube 3 years ago from Ekwulobia, Anambra, Nigeria

      I had my period 25th to 29th dec2013 ,,26 to 30th january 2014,wen am i ovulating,,wen is my most fertile days,,nd if i had sex 4th nd 5th febuary,,can i get pregnant??

    • profile image

      olivin 3 years ago

      i want to know when i will be ovulating after my menstrual cycle .i stars

      my period in 10 February 2014 and i will end in 14 February 2014 so pls tell me my ovulating time so that i can have sex to able to get pregnant

    • profile image

      Keri 3 years ago

      My period comes on the 22 of every month, reg. periods. Can u help me please than you

    • profile image

      sheba 3 years ago

      Hi I sopose to have my period the 15 and don't come as yet have sex last. I am wondering if I am pregant. Can't somebody answer my questuon

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      Misscalculation 3 years ago

      I had unprotected sex with my husband on CD 10, which also happened to be the last day of my period. I started on january ten and ended the 19th. Since my period is so long , does this affect when i ovulate or might there be a chance we will conceive? Im usually on about a 28-29 day cycle. Thanks!

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