← Calculators

Period calculator: predict when your next period will arrive

Enter the first day of your last period and your typical cycle length to estimate your next few periods.

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This is a general estimate from typical cycle math, not personalized medical advice — actual timing varies person to person and cycle to cycle. Nothing you enter here is saved unless you create a Masik account.

A straight-line repeat of your average cycle length like this gets less accurate the further out it goes — Masik's prediction engine improves on this by filtering outlier cycles and adapting as you log more. Create a free account to get real predictions from your own cycle history.