Enter the first day of your last period, your usual cycle length and how long your period lasts to see your next 6 expected periods. It's free, and nothing you enter is saved or sent anywhere.
What Counts as a Normal Cycle?
The NHS says the average cycle is 28 days, but anywhere from 21 to 40 days is normal, and periods usually last 2 to 7 days. Cycles can vary a little from month to month.
When Predictions Get Less Reliable
Periods are harder to predict with PCOS, after stopping hormonal contraception, after pregnancy and in perimenopause, when cycles often get shorter or longer. Tracking a few months of real dates gives you a better picture than any calculator.
When to See a Doctor
See a GP if your periods suddenly change, become very heavy, last longer than usual, or if you bleed between periods or after sex. Want to know your fertile days too? Try our ovulation calculator.
Free printable
Perimenopause symptom & cycle tracker
Track your periods, sleep, hot flashes and mood on one page, then bring it to your appointment. Enter your email to download it.
About the author: Jessica Bordo writes Daily Health Cycle out of personal interest in women's health, not as a clinician. Each guide summarizes what sources such as the NHS, NICE and published studies say, and links to them so you can check the claims yourself. Use these guides to prepare questions for your own clinician, not to replace their advice.
This tool gives estimates for general education and isn't medical advice or a method of contraception. See our full disclaimer.