Understandyour cycle
Free ovulation and cycle calculators, grounded in trusted medical sources, to help you understand your body’s rhythm. Everything is calculated locally — your data never leaves your device.
🔒 Calculated locally — your dates never leave your device
Browse by topic
Every part of your cycle — clear, sourced, and practical.
Ovulation & fertility
Understand when you ovulate, read the signs of your fertile wind…
Pregnancy & early signs
From your due date and how many weeks pregnant you are, to early…
Periods & your cycle
Predict your next period, understand a normal cycle, and decode …
Birth control & the safe period
Honest, evidence-based answers on the “safe period” and how reli…
Free cycle calculators
Calculated on your device · no sign-up needed.
Ovulation calculator
Ovulation usually happens about 14 days before your next period.…
Due date calculator
Your estimated due date is about 280 days (40 weeks) after the f…
Period calculator
Your next period is expected one cycle length after your last on…
Safe period calculator
The "safe period" is the part of your cycle when conception is l…
Popular guides
Answers to the questions women ask most.
Is the “safe period” reliable for avoiding pregnancy?
No. The “safe period” (calendar or rhythm method) is not reliable contraception. Even calculated…
Read more → PregnancyEarly pregnancy symptoms: the first signs
Early pregnancy signs — tender breasts, fatigue, nausea, frequent urination and mood changes — c…
Read more → PeriodsWhy is my period late?
A period that is up to about 7 days late is usually normal. If you are sexually active and more …
Read more → PregnancyImplantation bleeding vs period: how to tell them apart
Implantation bleeding is light pink or brown spotting that can occur about 10–14 days after ovul…
Read more → Birth controlBirth control methods compared
The most reliable birth control methods are long-acting ones — the implant and the IUD — with un…
Read more → OvulationOvulation discharge: what it looks like
Near ovulation your cervical mucus usually becomes clear, slippery and stretchy — much like raw …
Read more →Why you can trust this site
Every calculation runs locally with nothing uploaded; medical content cites references and will carry a named clinical review; where a method is unreliable (like calendar “safe days”), we say so — failure rates included.
Editorial & review policy →Private by design
Every calculation runs locally in your browser. We collect and upload nothing.
Traceable sources
Medical content cites WHO, ACOG and CDC — every claim is checkable.
Honest, never hyped
For unreliable methods (like calendar “safe days”) we state the real failure rate.