Conception date calculator
Conception ≈ LMP + 14 days (or due date − 266 days).
- Estimated conception date
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- Conception window (±2 days)
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Standard estimate assumes ovulation on day 14 of a 28-day cycle. Adjust cycle length above to shift accordingly.
About this tool
Conception date calculator is a single-purpose utility on instant.tw, a free toolbox of calculators, converters, generators, and quick lookups. Everything works in your browser — nothing is uploaded, nothing is stored on a server unless explicitly noted.
Category: Date & Time Tools. Browse more Date & Time Tools tools.