Period Duration Calculator
How many days your periods last, with a trend chart. Free, private and instant.
How to use the Period Duration
- Add one row per entry for your recent periods: First day or Last day.
- Press Calculate to get an instant result with a colour scale, chart and plain-English explanation.
About the Period Duration
Log the first and last day of recent periods to see how long each one lasted, your average period length and whether you are in the typical range of 2 to 7 days.
Also known as: period length calculator, how many days is my period, period duration, how long does my period last.
Formula and cut-offs
Duration = last bleeding day - first bleeding day + 1. Typical period length is 2 to 7 days. Longer than 7 days is prolonged.
Frequently asked questions
How long should a period last?
Between 2 and 7 days, with an average of about 5.
When is a long period a problem?
If bleeding lasts more than 7 days or soaks a pad or tampon every 1 to 2 hours, see a doctor.
Is a 2 day period normal?
Yes, if it is your usual pattern. A sudden change is worth mentioning to a doctor.
Sources and references
Written and checked by the MediHub editorial team against the sources above. Read how we build and review our calculators.
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Last updated . This calculator is for education only and is not medical advice. See the medical disclaimer.