Compare calculators
Both calculators run independently β change the inputs on either side to compare results.
Pregnancy
Pregnancy Week Calculator
Tells you how many weeks pregnant you are from how many days have passed since your reference date (LMP, conception, or due date), with a cycle-length adjustment in days.
Fill in the required fields to see your result.
Pregnancy
Conception Date Calculator
Estimates the most likely conception date by counting back 266 days (38 weeks) from your due date. Useful when you know your due date but want to narrow down when fertilization likely occurred.
Fill in the required fields to see your result.
Key differences
| Pregnancy Week Calculator | Conception Date Calculator | |
|---|---|---|
| Category | Pregnancy | Pregnancy |
| Inputs required | 3 | 1 |
| Result | Current Pregnancy Week (weeks) | Days since conception (days ago) |
| What it does | Tells you how many weeks pregnant you are from how many days have passed since your reference date (LMP, conception, or due date), with a cycle-length adjustment in days. | Estimates the most likely conception date by counting back 266 days (38 weeks) from your due date. Useful when you know your due date but want to narrow down when fertilization likely occurred. |