How It Works
Next period=LMP+cycle length. Calendar ovulation estimate=next period−14 days. Approximate fertile window=5 days before through 1 day after that estimate.
Scope and Limitations
- Cycle timing varies; this is not reliable contraception, a fertility diagnosis or confirmation of ovulation. Irregular cycles require another approach.
Reference Sources
FAQs
How does this calculator work?
Next period=LMP+cycle length. Calendar ovulation estimate=next period−14 days. Approximate fertile window=5 days before through 1 day after that estimate.
What assumptions should I check?
Cycle timing varies; this is not reliable contraception, a fertility diagnosis or confirmation of ovulation. Irregular cycles require another approach.