Cycle calculators & trackers
Six free tools to understand your cycle, predict your period, and check your PMS symptoms. No account required.
Irregular Cycle Predictor
NewEnter several past period dates and get a prediction from the median of your own cycles — with the working shown, and no 28-day default.
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Cycle Calculator
Most popularEnter your last period date and cycle length to predict your next period, ovulation day, and fertile window.
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Ovulation Calculator
Find your fertile window and peak ovulation day. Useful for understanding your most fertile days.
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Period Due Date Calculator
See exactly when your next period is due and how many days away it is — with an ovulation window too.
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Luteal Phase Calculator
Calculate the length of your luteal phase and find out if it falls within the normal range.
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PMS Symptom Checker
QuizRate 10 premenstrual symptoms on a 1–5 scale and get a PMS severity score with guidance on next steps.
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Track across multiple cycles
Calculators give you a one-time estimate. Dawn Phase tracks your actual patterns and improves predictions every cycle — free, and we never sell your data.
Start tracking free →Free · No credit card required
For informational purposes only. Dawn Phase is not a medical device, not contraception, and not a substitute for advice from a qualified healthcare provider.