Emergency Contraception Time Window Calculator

How many hours you have left for each emergency option. Free, private and instant.

How to use the Emergency Contraception Window

  1. Pick metric (cm, kg) or imperial (ft, in, lb) units.
  2. Pick date of unprotected sex.
  3. Set approximate time.
  4. Enter your weight (optional) - optional.
  5. Press Calculate to get an instant result with a colour scale, chart and plain-English explanation.

About the Emergency Contraception Window

Emergency contraception works best the sooner it is used. Enter when unprotected sex happened and see how many hours remain for the levonorgestrel pill (72 hours), ulipristal (120 hours) and the copper IUD (5 days).

Also known as: morning-after pill time calculator, emergency contraception time limit, levonorgestrel 72 hours, ulipristal 120 hours.

Formula and cut-offs

Levonorgestrel pill: best within 72 hours (some effect to 96 h). Ulipristal pill: up to 120 hours. Copper IUD: up to 5 days (120 hours), the most effective option.

Frequently asked questions

How long after sex can I take the morning-after pill?

Levonorgestrel pills work best within 72 hours, ulipristal within 120 hours, and a copper IUD can be fitted up to 5 days after.

Does the morning-after pill work if I am already pregnant?

No, it does not end an existing pregnancy.

Does weight affect emergency contraception?

Levonorgestrel pills may be less effective at a higher body weight. Ask about ulipristal or a copper IUD.

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.