Pregnancy & Family

Ovulation calculator

Expected ovulation – around 14 days before the next period.

Updated on Apr 21, 2026 Calculator, calculation path and examples on one page

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Calculator

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Calculation path

Step by step

  1. Estimate next period

    Result: May 5, 2026

  2. Calculate back 14 days

    Result: Apr 21, 2026

Instructions

How to use this calculator correctly

How to use the calculator

  • Enter the first day of the last period.
  • Estimate cycle length or derive it from several cycles.

Limits of the calculation

  • This is a mathematical approximation without hormonal measurement.

Common mistakes

  • Mixing up the start and end of the cycle.
  • Expect a fixed cycle length, although it varies greatly.

Related guide: Better understand week of pregnancy, ovulation and fertile days

Examples

Typical calculations

Slightly longer cycle.

30 day cycle

Expected ovulation: Apr 17, 2026

Load this example

FAQ

Frequently asked questions

Is ovulation always exactly 14 days before your period?

No, this is just an approximation. The actual luteal phase may vary.

Can the calculator help with irregular cycles?

Only limited. The more irregular the cycle, the less accurate the estimate.

What is the fertile phase?

As a guide, a time window of a few days before to shortly after ovulation is usually considered.

Can I use this to safely plan or rule out a pregnancy?

No. The calculator only provides guidance.

Why should I observe multiple cycles?

Because the actual cycle length may vary.

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Sources and notes

Rule status and context

methodology
Ovulation approximately 14 days before the next period.