Free online period calculator — predict your next menstrual period from last period date and cycle length.
Period Calculator Online
Period Calculator Online. Predict next period start date. Fast, accurate, private.
Next period starts
Tue, Aug 4, 2026
Expected endSat, Aug 8, 2026
Following cycleTue, Sep 1, 2026
Steps
- Open the calculator
- Enter your values
- Read the result instantly
Related
FAQ
Are results official?
No — quick estimates only. Confirm with your bank or provider.
Is data saved?
No. Calculations run in your browser.
Where is the full tool?
Each satellite links back to the main hub calculator.