LMP Apr 1, 2026, 28 day cycle
- Gestational age today
- 4w 0d
- Estimated conception
- Apr 15, 2026
- Trimester
- First trimester
Due Date Calculator
Use this free due date calculator to estimate expected delivery date from the first day of the last period and cycle length.
Research-based formula Estimate limits shown Examples included Private history
Formula steps
- Start with the first day of the last menstrual period.
- Add 280 days, adjusting for cycle length compared with a 28-day cycle.
- Estimate conception near ovulation, about 14 days before the next period.
How to use the due date calculator
- Enter the requested measurements, dates, lab values, or workout details.
- Check that the units and formula assumptions match what the tool is asking for.
- Press the calculate button to see the answer, supporting metrics, and formula steps.
- Read the estimate with the health disclaimer in mind, then copy the result if you need it for notes.
Common uses
Estimate a due date from last menstrual period.
Adjust the estimate for shorter or longer cycles.
Find estimated conception date alongside due date.
Use as a planning reference before clinical confirmation.
Examples
Estimated due date Jan 6, 2027
Cycle-adjusted estimate
Cycle-adjusted estimate
Frequently asked questions
Quick answers about formulas, inputs, estimate limits, professional guidance, examples, and private in-browser history.
What can I use the Due Date Calculator for?
Use it for quick educational estimates, planning, comparison, and trend checks. Health and fitness results should be interpreted with context, not as a diagnosis.
How does the Due Date Calculator calculate the result?
The calculator uses Naegele-style dating: LMP plus 280 days, adjusted by the difference from a 28-day cycle.
Is this medical advice?
No. This page provides an educational estimate only. Talk with a qualified health professional before making medical, pregnancy, nutrition, medication, or safety decisions.
Are my health inputs private?
Yes. The calculator runs in your browser tab. Recent answers stay only on the page while you use it and are not sent to a server.