Conception Calculator

Estimate when conception occurred based on your due date or birth date.

This calculator estimates when conception likely occurred based on your due date. Results are approximate as exact conception timing is difficult to determine.

Most Likely Conception Date

May 12, 2026

Possible Conception Window

Earliest

Thu, May 7

Latest

Thu, May 14

Daily Conception Likelihood

Thu, May 7
3%
Fri, May 8
8%
Sat, May 9
14%
Sun, May 10
27%
Mon, May 11
31%
Tue, May 12
33%
Wed, May 13
2%
Thu, May 14
2%

Likelihood Distribution

Thu, May 7(2.5%)
Fri, May 8(6.7%)
Sat, May 9(11.7%)
Sun, May 10(22.5%)
Mon, May 11(25.8%)
Tue, May 12(27.5%)
Wed, May 13(1.7%)
Thu, May 14(1.7%)

These dates are estimates. Sperm can survive up to 5 days, making exact conception dates uncertain.

How Conception Date is Calculated

Conception typically occurs about 266 days before the due date, during ovulation. The fertile window spans about 6 days, with the highest chances on ovulation day and the day before.

Factors Affecting Conception

Sperm can survive in the reproductive tract for up to 5 days, while an egg survives only 12-24 hours after ovulation. This means conception can occur from intercourse that happened several days before ovulation.

Accuracy Considerations

Conception date calculations are estimates. The actual conception could have occurred anywhere within the fertile window, making it difficult to pinpoint the exact date.

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