How accurate is a due date calculator?

Only about 5% of babies are born on their exact due date. Most arrive within 2 weeks before or after.

Pregnancy Due Date Calculator

GoCalc

Estimate your due date and track pregnancy progress

Calculation Method

First Day of Last Period

Estimated Due Date

Current Week

Days Remaining

1st Trimester

Weeks 1-12

2nd Trimester

Weeks 13-26

3rd Trimester

Weeks 27-40

How is the due date calculated?+

Using Naegele's rule: add 280 days (40 weeks) to the first day of your last menstrual period.

How accurate is this?+

Only ~5% of babies arrive on the exact due date. Most come within 2 weeks before or after.

What trimester am I in?+

1st: weeks 1-12, 2nd: weeks 13-26, 3rd: weeks 27-40.

Does it show the work?

Yes, step-by-step breakdowns are provided so you can follow the calculation logic.

Can I save my calculations?

Results can be copied to clipboard. Use the Copy or Print button for a permanent record.

How is the result calculated?

Uses standard mathematical formulas widely accepted in the field. The formula is shown with each result.

What if I get an unexpected result?

Double-check your input values and units. The tool validates inputs and shows error messages.

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