Period Calculator
Estimates your next expected period date from your last period and cycle length.
Lilu Baba's Period Calculator projects your next expected period by adding your average cycle length to your last period's start date. Informational only, not medical advice.
How to use this calculator
- Enter the first day of your last period.
- Enter your average cycle length.
- Your next expected period date updates instantly.
Next Expected Period
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FAQ
Period Calculator — frequently asked questions
This estimate assumes a consistent cycle length — irregular cycles will be less predictable, so track over a few months for a more reliable average.
Yes — many factors including stress, illness, travel and lifestyle changes can shift your actual cycle from this estimate.