Due Date Formula: Due Date ~= Conception Date + 266 days

Due Date Definition The Due Date Calculator is a pregnancy calculator that will calculate your approximate due date based on the date of your last period. Simply enter in the date of your last period and the Pregnancy Due Date Calculator will calculate the estimated date of conception!

How to Calculate Due Date Let's be honest - sometimes the best due date calculator is the one that is easy to use and doesn't require us to even know what the due date formula is in the first place! But if you want to know the exact formula for calculating due date then please check out the "Formula" box above.