ToolnozaHEALTH TOOL
Ovulation Calculator — Estimated Dates
Estimate an ovulation date and a calendar fertile window from a regular cycle.
Ovulation Calculator — Estimated Dates
FREE ONLINE TOOLSTEP BY STEP
How to use ovulation calculator — estimated dates
- Enter the labelled values in the displayed units.
- Review the method: Next period = last period start + cycle length; estimated ovulation = next period − assumed luteal phase. Display window = 5 days before estimated ovulation through 1 day after.
- Read the worked example and method limitations.
WHEN IT HELPS
Common uses
- Compare the assumptions: Starting 1 October 2026 with a 28-day cycle and assumed 14-day luteal phase: next period 29 October, estimated ovulation 15 October.
IN PRACTICE
Example
Starting 1 October 2026 with a 28-day cycle and assumed 14-day luteal phase: next period 29 October, estimated ovulation 15 October.
GOOD TO KNOW
Can these dates prevent pregnancy?
No. Calendar estimates cannot confirm ovulation or identify safe days. Timing varies, especially with irregular cycles, postpartum changes or hormonal contraception. Never use this calculator as contraception.
Frequently asked questions
Can these dates prevent pregnancy?
No. Calendar estimates cannot confirm ovulation or identify safe days. Timing varies, especially with irregular cycles, postpartum changes or hormonal contraception. Never use this calculator as contraception.
Which formula is used?
Next period = last period start + cycle length; estimated ovulation = next period − assumed luteal phase. Display window = 5 days before estimated ovulation through 1 day after.