Due Date from Conception Calculator
Estimated due date = conception + 266 days. Not medical advice.
Result
Estimated due date
2026-10-08
Conception + 266 days.
- Conception2026-01-15
- Equivalent LMP (~14d before)2026-01-01
- Estimated due date2026-10-08
- Day of week (due)Thursday
Step-by-step
- Conception + 266 days = 2026-10-08.
- (Equivalent to LMP + 280 days, since conception ≈ LMP + 14.)
How to use this calculator
- Enter known or estimated conception date.
- Read estimated due date.
About this calculator
A "term" pregnancy is 266 days from conception (38 weeks), equivalent to 280 days from LMP. Conception date is rarely known precisely; LMP-based dating is more common in clinical practice. Not medical advice.
Frequently asked
Because LMP is conventionally ~14 days before conception. Both formulas (LMP+280, conception+266) give the same answer.
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