Conception Calculator
Estimate when you conceived based on your due date, last period, or ultrasound. Calculate your fertile window and implantation dates.
Conception typically occurs around ovulation, about 14 days before your next period. Sperm can survive up to 5 days, widening the possible conception window.
Enter your information below to estimate when conception occurred.
Calculate Conception Date
Enter your estimated due date as provided by your healthcare provider.
Why Choose Forge Conception Calculator?
Unlike Flo App, Ovia and BabyCenter, Forge Conception Calculator offers a genuinely free, private, and unlimited experience with no strings attached.
100% Free Forever
No hidden fees, no premium tiers, no limits.
Complete Privacy
Everything runs in your browser. We never see your data.
No Signup Required
Use instantly without creating an account.
Unlimited Use
No daily limits, no credits, no restrictions.
Last updated: January 2026 • Built with care by iForge Apps
How to use this tool
Select your calculation method (Due Date, Last Period, or Ultrasound)
Enter the required date and any additional information
Click 'Calculate Conception' to see results
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