Ovulation Calculator

Estimate ovulation by subtracting the luteal-phase length from your usual cycle length. This is educational timing information, not contraception or a guarantee of fertility.

Ovulation Calculator

Estimate ovulation by subtracting the luteal-phase length from your usual cycle length. This is educational timing information, not contraception or a guarantee of fertility.

Method and assumptions

Figur applies straightforward arithmetic to the values you enter. The calculation runs locally in your browser and is not stored.

  • The result depends on accurate inputs and units.
  • External factors, fees, taxes, or rules not requested by the calculator are not included.
  • Use the result as a planning estimate and verify any high-stakes decision.

Sources and references

No external data source is required: this calculator uses standard arithmetic and the values you enter.

Frequently asked questions

Can I use this to prevent pregnancy?

No. Ovulation can vary; use a reliable contraceptive method and speak with a clinician for guidance.

What is the fertile window?

Sperm can survive for several days, so conception may be possible in the days before and around ovulation.