Ovulation Calculator — Estimated Date Calculator
Date & TimeOvulation Calculator is a date tool that estimates ovulation date and fertile window from average cycle length from the last menstrual period and cycle information.
Important basis and limitations
- Basis date
- Content basis date: 2026-06-25
- Scope
- A general reference date calculation
Reference sources
This is a reference calculation from public sources and your inputs. It may not reflect personal circumstances, recent changes, or an authority’s interpretation. Confirm with an official source or qualified professional before filing, contracting, clinical care, contraception, or another important decision.
What is it
Ovulation Calculator calculates a reference estimate in your browser. Actual dates can vary by cycle pattern, ultrasound findings, and clinical assessment, so this tool should not be used for medical decisions or contraception.
How to use
- 1Enter the first day of the last menstrual period.
- 2Enter average cycle length when needed.
- 3Press calculate to see the reference estimate.
Reference
| Input | Result |
|---|---|
| 2026-01-01 | estimates ovulation date and fertile window from average cycle length |
Sources & standards
- Office on Women’s Health: Ovulation Calculator - U.S. Office on Women’s Health
FAQ
Is Ovulation Calculator a diagnosis?
No. This tool provides a general date-based estimate and does not replace clinical care or medical judgment.
Is Ovulation Calculator input sent to a server?
No. This tool runs in your browser and does not send input to a server.