Calculate the date of ovulation, days favorable for conception, and the next menstruation. Free online cycle calculator for women.
Calculate the date of ovulation, days favorable for conception, and the next menstruation. Free online cycle calculator for women.
The cycle may vary by ±2 days, especially with stress or climate change.
The results are approximate and do not replace consultation with a doctor.
Keep a menstruation calendar for more accurate calculations.
An ovulation calculator will help you calculate the optimal days for conception and find out the date of your next menstruation. Just enter the start date of your cycle and its duration - and you will receive a personalized fertility calendar.
Ovulation calculation is based on the calendar method and is suitable for women with a regular cycle. To increase accuracy, it is recommended to keep a menstruation calendar for several months and combine the calendar method with other methods of determining ovulation.
Let's look at practical examples of calculating ovulation for different types of cycles:
Last menstruation March 1, cycle 28 days
Входные данные:
Date of last menstruation: March 1
Cycle length: 28 days
Duration of menstruation: 5 daysРасчёт:
Ovulation date = March 1 + (28 - 14) = March 1 + 14 = March 15
Fertile period: March 13-16 (4 days)
Next menstruation: March 29Результат:
Ovulation: March 15
Фертильные дни:
Fertile days: March 13-16
Last menstruation April 5, cycle 24 days
Входные данные:
Date of last menstrual period: April 5
Cycle length: 24 days
Duration of menstruation: 4 daysРасчёт:
Ovulation date = April 5 + (24 - 14) = April 5 + 10 = April 15
Fertile period: April 13-16 (4 days)
Next menstruation: April 29Результат:
Ovulation: April 15
Фертильные дни:
Fertile days: April 13-16
Last menstruation May 10, cycle 32 days
Входные данные:
Date of last menstrual period: May 10
Cycle length: 32 days
Duration of menstruation: 6 daysРасчёт:
Ovulation date = May 10 + (32 - 14) = May 10 + 18 = May 28
Fertile period: May 26-29 (4 days)
Next menstruation: June 11Результат:
Ovulation: May 28
Фертильные дни:
Fertile days: May 26-29
Last menstruation June 15, average cycle length 28 days
Входные данные:
Date of last menstrual period: June 15
Average cycle length: 28 days
Duration of menstruation: 5 daysРасчёт:
Ovulation date ≈ June 15 + 14 = June 29
Fertile period: June 27-30
⚠️ With an irregular cycle, accuracy decreasesРезультат:
Ovulation: ~June 29 (approx.)
Фертильные дни:
It is recommended to use additional methods
Cycle 30 days, last menstruation July 1
Входные данные:
Date of last menstrual period: July 1
Cycle length: 30 days
Goal: Pregnancy planningРасчёт:
Ovulation date = July 1 + (30 - 14) = July 1 + 16 = July 17
Fertile period: July 15-18
Optimal days for conception: July 15-17Результат:
Ovulation: July 17
Фертильные дни:
Optimal days for conception: July 15-17
Last menstruation August 20, cycle 26 days
Входные данные:
Date of last menstrual period: August 20
Cycle length: 26 days
Duration of menstruation: 5 daysРасчёт:
Ovulation date = August 20 + (26 - 14) = August 20 + 12 = September 1
Fertile period: August 30 - September 2
Next menstruation: September 15Результат:
Ovulation: September 1
Фертильные дни:
Next menstruation: September 15
Ovulation usually occurs 14 days before the start of your next period. The fertile period includes 2 days before ovulation, the day of ovulation and 1 day after it.
The menstrual cycle can have different durations:
| Cycle type | Duration (days) | Ovulation day | Comment |
|---|---|---|---|
| Short cycle (21-24 days) | 21–24 days | 7–10 | Ovulation on days 7-10. Frequent cycle, but within normal limits. |
| Normal cycle (25-30 days) | 25–30 days | 12–15 | Ovulation on days 12-15. The most common type of cycle. |
| Long cycle (31-35 days) | 31–35 days | 17–21 | Ovulation on days 17-21. Less common, but acceptable. |
Our ovulation calculator provides many benefits:
Quick calculation in a few seconds
Accurate calculations based on medical data
Completely free without registration
Support 4 languages (Russian, English, Spanish, German)
Responsive design for all devices
Visual calendar with color markings
For a more accurate calculation of ovulation, follow these recommendations:
Keep a menstrual calendar for at least 3 months
Notice the regularity of your cycle
Consult your doctor if you have an irregular cycle
Lead a healthy lifestyle: proper nutrition, physical activity
Ovulation is the process of the release of a mature egg from the ovary into the fallopian tube. This occurs around the middle of the menstrual cycle and is the most favorable time for conception. The egg is viable for 12-24 hours after ovulation.
Fertile days are the period when the likelihood of conception is highest. Usually this is 2-3 days before ovulation, the day of ovulation and 1 day after it. Sperm can live in a woman’s body for up to 5-7 days, so intercourse a few days before ovulation can also lead to conception.
The normal length of the menstrual cycle is 21-35 days, with an average of 28 days. A cycle is considered regular if its duration does not change by more than 2-3 days. The first day of the cycle is the first day of menstruation.
The calculator gives approximate results based on standard medical data. Accuracy depends on the regularity of your cycle. With a regular cycle, the accuracy is about 80-90%. If you have an irregular cycle, it is recommended to use additional methods to determine ovulation (tests, basal temperature) and consult a doctor.
The day of ovulation is calculated using the formula: Date of last menstruation + (Cycle length - 14) days. For example, with a 28-day cycle and the last menstruation on March 1: ovulation = March 1 + (28 - 14) = March 15. Ovulation usually occurs 14 days before the start of your next period.
Fertile days are calculated as follows: 2-3 days before ovulation, the day of ovulation and 1 day after ovulation. For example, if ovulation is on March 15, then fertile days are March 13-16 (4 days). This is the period of maximum probability of conception.
The next period begins the length of your cycle after your last period. For example, with the last menstruation on March 1 and a cycle of 28 days, the next menstruation will begin on March 29. The duration of menstruation is usually 3-7 days.
Yes, the day of ovulation is one of the most favorable days for conception. The probability of conception on the day of ovulation is maximum (up to 33%). However, to increase your chances, it is also recommended to try to conceive 2-3 days before ovulation, since sperm can live in the body for several days.
Theoretically possible, but unlikely. The likelihood of conceiving during menstruation is very low, but not zero, especially with a short cycle (21-24 days) or early ovulation. Sperm can remain viable for up to 7 days, so fertilization is possible with a short cycle.
The day of ovulation is affected by: stress, climate change, illness, medication, weight changes, physical activity, hormonal changes. These factors can push ovulation several days earlier or later, which reduces the accuracy of the calendar method.
You can determine ovulation: by ovulation test (shows a surge in LH), measuring basal temperature (increase by 0.3-0.5 ° C), observing cervical mucus (becoming transparent and viscous), ultrasound monitoring, signs (pain in the lower abdomen, increased libido).
The short cycle is 21-24 days. With this cycle, ovulation occurs earlier - usually on days 7-10 of the cycle. This is normal, but important to consider when planning a pregnancy. With a short cycle, the fertile period begins earlier.
The long cycle is 31-35 days or more. With this cycle, ovulation occurs later - usually 17-21 days or later. This is also normal. With a long cycle, the fertile period shifts accordingly, and menstruation comes later.
Keep a calendar, noting: the first day of each menstruation, the duration of menstruation, the length of the cycle (the number of days from the first day of one menstruation to the first day of the next), well-being, signs of ovulation. Keep a calendar for at least 3-6 months to determine your average cycle length.
An irregular cycle is when your cycle length varies significantly (more than 7 days) between cycles. For example, one cycle is 25 days, the next is 35 days. If you have an irregular cycle, the calendar method is less accurate; it is recommended to consult a doctor and use other methods for determining ovulation.
The calendar method (Ogino-Knaus method) has low effectiveness for prevention (Pearl index 9-25). It is not recommended as a primary method of contraception. For protection, it is better to use more reliable methods (condoms, hormonal contraceptives, IUDs).
To increase accuracy: keep a menstrual calendar for at least 3-6 months, take into account the average length of the cycle, use additional methods (ovulation tests, basal temperature), monitor the signs of ovulation, take into account factors affecting the cycle (stress, illness).
A pregnancy test can be taken no earlier than 10-14 days after ovulation (or after the expected date of the next menstruation). Earlier, the test may show a false negative result because the hCG level is still too low to detect.
The luteal phase is the period after ovulation until the next menstruation begins. Usually 12-16 days, average 14 days. If the luteal phase is shorter than 10 days, this may indicate problems with conception and requires consultation with a doctor.
Stress can delay ovulation or make your cycle irregular. Under severe stress, ovulation may occur later than usual or not at all (anovulatory cycle). Stress management is important for cycle regularity and successful conception.
An anovulatory cycle is a menstrual cycle in which ovulation does not occur. Menstruation may come, but ovulation has not occurred. Such cycles can occur 1-2 times a year and are considered normal. Frequent anovulatory cycles require consultation with a doctor.
With age (after 35 years), ovulation may become irregular, cycles may lengthen or shorten. The number of eggs decreases, which affects fertility. Teenage girls may also have irregular cycles in the first years after menarche.
Possibly, especially with a short cycle. If the cycle is 21-24 days, and menstruation lasts 5-7 days, ovulation can occur as early as 7-10 days of the cycle. Sperm can live up to 7 days, so intercourse immediately after menstruation can lead to conception if you ovulate early.
Basal temperature is the body temperature at rest, measured immediately after waking up. During ovulation, the temperature rises by 0.3-0.5°C and remains elevated until menstruation. Measure your temperature in the morning, without getting out of bed, at the same time, with the same thermometer.
An ovulation test measures the level of luteinizing hormone (LH) in the urine. 24-36 hours before ovulation there is a surge in LH, which is recorded by the test. A positive test means that ovulation will occur within the next 24-36 hours. This is a more accurate method than the calendar method.
Signs of ovulation: pain in the lower abdomen (moderate pain), increased libido, changes in cervical mucus, increased basal temperature, positive ovulation test. The combination of the calendar method with observation of signs increases the accuracy of determining fertile days.
For an irregular cycle: keep a calendar for at least 6 months to determine the average length, use additional methods (tests, basal temperature), consult a gynecologist to identify the causes of irregularity, eliminate stress factors, normalize weight and nutrition.
Yes, some medications can affect ovulation: hormonal drugs, antidepressants, anti-inflammatory drugs, chemotherapy. Oral contraceptives suppress ovulation. After canceling OK, the cycle may not be restored immediately. When taking medications, consider their effect on your cycle.
Nutrition affects ovulation: nutritional deficiencies, crash diets, and being overweight or underweight can disrupt your cycle and ovulation. For normal ovulation, a balanced diet with sufficient amounts of proteins, fats, carbohydrates, vitamins and minerals is important.
You should consult a doctor: if you have not been able to get pregnant for more than a year (or 6 months if you are over 35 years old), with an irregular cycle, in the absence of ovulation, with health problems affecting fertility. The doctor may prescribe examination and treatment.