Pregnancy Due Date Calculator
Due date and trimester milestones from your last period.
Enter your values
ⓘ Live results
Results
- Days until due date
- 210 days
- Gestational age
- 10 weeks 0 days
- Current trimester
- First trimester
- Progress
- 25%
Quick answer
Naegele's rule sets the due date 280 days after the first day of the last menstrual period, adjusted for cycle length.
Due date = LMP + 280 days
How to use the Pregnancy Due Date Calculator
- 1Count the days since your last period began.
- 2Enter your usual cycle length.
- 3Read the due date countdown and trimester.
Worked example
Using the values the calculator loads with:
Inputs
- Days since your last period started70 days
- Usual cycle length28 days
Results
- Days until due date210 days
- Gestational age10 weeks 0 days
- Current trimesterFirst trimester
- Progress25%
Frequently asked questions
How accurate is the due date?
Only about 4% of babies arrive on the exact date; 80% arrive within two weeks either side.
What if my cycle is not 28 days?
The tool shifts the due date by the difference, since ovulation timing moves with cycle length.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.