Cycles & ovulation

On a 21-day cycle, ovulation usually happens around cycle day 7. See your fertile window and example dates.

With a 21-day cycle, your fertile window is roughly cycle days 2 to 7. Here's how it's worked out.

The highest chance of pregnancy on a 21-day cycle is around cycle days 5 to 7. Learn why.

On a 21-day cycle, the most reliable day to test is cycle day 22, when your period is due. Earliest testing starts around day 17.

A 21-day cycle shifts the standard due date by -7 days. See how to adjust your due date and conception date.

On a 22-day cycle, ovulation usually happens around cycle day 8. See your fertile window and example dates.

With a 22-day cycle, your fertile window is roughly cycle days 3 to 8. Here's how it's worked out.

The highest chance of pregnancy on a 22-day cycle is around cycle days 6 to 8. Learn why.

On a 22-day cycle, the most reliable day to test is cycle day 23, when your period is due. Earliest testing starts around day 18.

A 22-day cycle shifts the standard due date by -6 days. See how to adjust your due date and conception date.

On a 23-day cycle, ovulation usually happens around cycle day 9. See your fertile window and example dates.

With a 23-day cycle, your fertile window is roughly cycle days 4 to 9. Here's how it's worked out.

The highest chance of pregnancy on a 23-day cycle is around cycle days 7 to 9. Learn why.

On a 23-day cycle, the most reliable day to test is cycle day 24, when your period is due. Earliest testing starts around day 19.

A 23-day cycle shifts the standard due date by -5 days. See how to adjust your due date and conception date.

On a 24-day cycle, ovulation usually happens around cycle day 10. See your fertile window and example dates.

With a 24-day cycle, your fertile window is roughly cycle days 5 to 10. Here's how it's worked out.

The highest chance of pregnancy on a 24-day cycle is around cycle days 8 to 10. Learn why.

On a 24-day cycle, the most reliable day to test is cycle day 25, when your period is due. Earliest testing starts around day 20.

A 24-day cycle shifts the standard due date by -4 days. See how to adjust your due date and conception date.

On a 25-day cycle, ovulation usually happens around cycle day 11. See your fertile window and example dates.

With a 25-day cycle, your fertile window is roughly cycle days 6 to 11. Here's how it's worked out.

The highest chance of pregnancy on a 25-day cycle is around cycle days 9 to 11. Learn why.

On a 25-day cycle, the most reliable day to test is cycle day 26, when your period is due. Earliest testing starts around day 21.

A 25-day cycle shifts the standard due date by -3 days. See how to adjust your due date and conception date.

On a 26-day cycle, ovulation usually happens around cycle day 12. See your fertile window and example dates.

With a 26-day cycle, your fertile window is roughly cycle days 7 to 12. Here's how it's worked out.

The highest chance of pregnancy on a 26-day cycle is around cycle days 10 to 12. Learn why.

On a 26-day cycle, the most reliable day to test is cycle day 27, when your period is due. Earliest testing starts around day 22.

A 26-day cycle shifts the standard due date by -2 days. See how to adjust your due date and conception date.

On a 27-day cycle, ovulation usually happens around cycle day 13. See your fertile window and example dates.

With a 27-day cycle, your fertile window is roughly cycle days 8 to 13. Here's how it's worked out.

The highest chance of pregnancy on a 27-day cycle is around cycle days 11 to 13. Learn why.

On a 27-day cycle, the most reliable day to test is cycle day 28, when your period is due. Earliest testing starts around day 23.

A 27-day cycle shifts the standard due date by -1 days. See how to adjust your due date and conception date.

On a 28-day cycle, ovulation usually happens around cycle day 14. See your fertile window and example dates.

With a 28-day cycle, your fertile window is roughly cycle days 9 to 14. Here's how it's worked out.

The highest chance of pregnancy on a 28-day cycle is around cycle days 12 to 14. Learn why.

On a 28-day cycle, the most reliable day to test is cycle day 29, when your period is due. Earliest testing starts around day 24.

A 28-day cycle shifts the standard due date by +0 days. See how to adjust your due date and conception date.

On a 29-day cycle, ovulation usually happens around cycle day 15. See your fertile window and example dates.

With a 29-day cycle, your fertile window is roughly cycle days 10 to 15. Here's how it's worked out.

The highest chance of pregnancy on a 29-day cycle is around cycle days 13 to 15. Learn why.

On a 29-day cycle, the most reliable day to test is cycle day 30, when your period is due. Earliest testing starts around day 25.

A 29-day cycle shifts the standard due date by +1 days. See how to adjust your due date and conception date.

On a 30-day cycle, ovulation usually happens around cycle day 16. See your fertile window and example dates.

With a 30-day cycle, your fertile window is roughly cycle days 11 to 16. Here's how it's worked out.

The highest chance of pregnancy on a 30-day cycle is around cycle days 14 to 16. Learn why.

On a 30-day cycle, the most reliable day to test is cycle day 31, when your period is due. Earliest testing starts around day 26.

A 30-day cycle shifts the standard due date by +2 days. See how to adjust your due date and conception date.

On a 31-day cycle, ovulation usually happens around cycle day 17. See your fertile window and example dates.

With a 31-day cycle, your fertile window is roughly cycle days 12 to 17. Here's how it's worked out.

The highest chance of pregnancy on a 31-day cycle is around cycle days 15 to 17. Learn why.

On a 31-day cycle, the most reliable day to test is cycle day 32, when your period is due. Earliest testing starts around day 27.

A 31-day cycle shifts the standard due date by +3 days. See how to adjust your due date and conception date.

On a 32-day cycle, ovulation usually happens around cycle day 18. See your fertile window and example dates.

With a 32-day cycle, your fertile window is roughly cycle days 13 to 18. Here's how it's worked out.

The highest chance of pregnancy on a 32-day cycle is around cycle days 16 to 18. Learn why.

On a 32-day cycle, the most reliable day to test is cycle day 33, when your period is due. Earliest testing starts around day 28.

A 32-day cycle shifts the standard due date by +4 days. See how to adjust your due date and conception date.

On a 33-day cycle, ovulation usually happens around cycle day 19. See your fertile window and example dates.

With a 33-day cycle, your fertile window is roughly cycle days 14 to 19. Here's how it's worked out.

The highest chance of pregnancy on a 33-day cycle is around cycle days 17 to 19. Learn why.

On a 33-day cycle, the most reliable day to test is cycle day 34, when your period is due. Earliest testing starts around day 29.

A 33-day cycle shifts the standard due date by +5 days. See how to adjust your due date and conception date.

On a 34-day cycle, ovulation usually happens around cycle day 20. See your fertile window and example dates.

With a 34-day cycle, your fertile window is roughly cycle days 15 to 20. Here's how it's worked out.

The highest chance of pregnancy on a 34-day cycle is around cycle days 18 to 20. Learn why.

On a 34-day cycle, the most reliable day to test is cycle day 35, when your period is due. Earliest testing starts around day 30.

A 34-day cycle shifts the standard due date by +6 days. See how to adjust your due date and conception date.

On a 35-day cycle, ovulation usually happens around cycle day 21. See your fertile window and example dates.

With a 35-day cycle, your fertile window is roughly cycle days 16 to 21. Here's how it's worked out.

The highest chance of pregnancy on a 35-day cycle is around cycle days 19 to 21. Learn why.

On a 35-day cycle, the most reliable day to test is cycle day 36, when your period is due. Earliest testing starts around day 31.

A 35-day cycle shifts the standard due date by +7 days. See how to adjust your due date and conception date.

On a 36-day cycle, ovulation usually happens around cycle day 22. See your fertile window and example dates.

With a 36-day cycle, your fertile window is roughly cycle days 17 to 22. Here's how it's worked out.

The highest chance of pregnancy on a 36-day cycle is around cycle days 20 to 22. Learn why.

On a 36-day cycle, the most reliable day to test is cycle day 37, when your period is due. Earliest testing starts around day 32.

A 36-day cycle shifts the standard due date by +8 days. See how to adjust your due date and conception date.

On a 37-day cycle, ovulation usually happens around cycle day 23. See your fertile window and example dates.

With a 37-day cycle, your fertile window is roughly cycle days 18 to 23. Here's how it's worked out.

The highest chance of pregnancy on a 37-day cycle is around cycle days 21 to 23. Learn why.

On a 37-day cycle, the most reliable day to test is cycle day 38, when your period is due. Earliest testing starts around day 33.

A 37-day cycle shifts the standard due date by +9 days. See how to adjust your due date and conception date.

On a 38-day cycle, ovulation usually happens around cycle day 24. See your fertile window and example dates.

With a 38-day cycle, your fertile window is roughly cycle days 19 to 24. Here's how it's worked out.

The highest chance of pregnancy on a 38-day cycle is around cycle days 22 to 24. Learn why.

On a 38-day cycle, the most reliable day to test is cycle day 39, when your period is due. Earliest testing starts around day 34.

A 38-day cycle shifts the standard due date by +10 days. See how to adjust your due date and conception date.

On a 39-day cycle, ovulation usually happens around cycle day 25. See your fertile window and example dates.

With a 39-day cycle, your fertile window is roughly cycle days 20 to 25. Here's how it's worked out.

The highest chance of pregnancy on a 39-day cycle is around cycle days 23 to 25. Learn why.

On a 39-day cycle, the most reliable day to test is cycle day 40, when your period is due. Earliest testing starts around day 35.

A 39-day cycle shifts the standard due date by +11 days. See how to adjust your due date and conception date.

On a 40-day cycle, ovulation usually happens around cycle day 26. See your fertile window and example dates.

With a 40-day cycle, your fertile window is roughly cycle days 21 to 26. Here's how it's worked out.

The highest chance of pregnancy on a 40-day cycle is around cycle days 24 to 26. Learn why.

On a 40-day cycle, the most reliable day to test is cycle day 41, when your period is due. Earliest testing starts around day 36.

A 40-day cycle shifts the standard due date by +12 days. See how to adjust your due date and conception date.