Evidence-led answers for everyday female body questions — without shame, scare tactics or sales pressure.

HerSensi tool

Cycle Variation Visualizer

Turn several period start dates into intervals, average length and range so you can see your own pattern clearly.

Cycle variation visualizer

Your result

Your answer will appear here

Nothing is prefilled. Add only the information you are comfortable using in this browser.

Private by defaultThis tool runs in your browser and does not diagnose you. Avoid entering identifying medical information you do not want to use here.
Safety boundary

The tool describes the dates you entered; it does not diagnose irregular periods or a hormonal condition.

Worked example

What this looks like in real life

Dates 2 May, 31 May and 29 June create two 29-day intervals — a much clearer story than simply saying your periods feel random.

If the intervals vary widely, that is a pattern to track, not a diagnosis by itself.

What the tool cannot tell you

Does not define what is medically normal for you.

Does not identify ovulation or fertility problems.

Very heavy bleeding, severe pain or pregnancy concerns need their own assessment.

Continue from the result

Use the answer, not just the calculator.