How do I use the Pregnancy Calculator?
Enter your values in the fields and the result updates instantly as you type.
Pregnancy Calculator
Calculate due date and pregnancy milestones from last menstrual period. Enter your values, review the formula, and use the worked result as a quick check for everyday planning.
Pregnancy Calculator
Calculate due date and pregnancy milestones from last menstrual period.
First day of last period (YYYY-MM-DD)
Results
Estimated Due Date
2024-10-07
Current Week
122 week 122
Days
4 days
Trimester
3 3rd
Formula: Due Date = LMP + 280 days
Pregnancy Due Date and Milestone Calculator
Estimate your due date and track pregnancy milestones based on the first day of your last menstrual period (LMP). The standard calculation adds 280 days (40 weeks) to the LMP to predict the estimated delivery date.
Formula
Due Date = LMP + 280 days. Pregnancy is counted from the first day of the last period, not the date of conception. The calculator also shows your current week, day of the current week, and which trimester you are in.
Worked example
LMP of January 1, 2024 produces an estimated due date around October 7, 2024. At the time of viewing, the calculator shows current week, remaining days, and trimester based on today's date.
Practical guidance
Pregnancy dating and ultrasound
The LMP method provides an initial estimate. Your healthcare provider will confirm or adjust the due date based on ultrasound measurements, which are more accurate for early pregnancy dating. This calculator is for general planning and awareness.
Trimester milestones
First trimester: weeks 1-13. Second trimester: weeks 14-26. Third trimester: week 27 to delivery. Each trimester has different development milestones and screening recommendations. Discuss your specific timeline with your healthcare provider.
Frequently asked questions
What formula does this calculator use?
Due Date = LMP + 280 days
Can I use decimal values?
Yes. Decimal inputs are supported for most calculators. Integer-based tools use rounded integer values where appropriate.
Is this calculator free?
Yes. CalcuNimble calculators are free and optimized for fast everyday use.