Free Pregnancy Due Date Calculator
Updated September 2026
Calculate your due date, current week of pregnancy, and trimester from the first day of your last menstrual period — free online pregnancy calculator.
Verified Capabilities
Adds 280 days to your LMP date to estimate your due date, current week, and days remaining.
Shows all three trimesters and highlights which one you're currently in.
Everything computes immediately in your browser from a single date input.
No conception-date input, no cycle-length adjustment (always assumes 28 days), and no week-by-week development milestone timeline beyond the three trimester ranges.
Understanding your health numbers is the foundation of informed wellness decisions. The Pregnancy Due Date Calculator uses clinically established formulas to provide science-backed estimates.
Calculate your due date, current week of pregnancy, and trimester from the first day of your last menstrual period — free online pregnancy calculator. Results are immediate — no waiting, no loading screens, no account required.
Who uses the Pregnancy Due Date Calculator?
- Pregnant women tracking their current week, trimester, and estimated due date.
- Partners and family members understanding the pregnancy stage and timeline.
- Couples planning around an expected due date for work leave, travel, and preparation.
Common uses and search terms
The Pregnancy Due Date Calculator is frequently used for: due date, pregnancy calculator, EDD, due date calculator, pregnancy due date calculator, when is my baby due, estimated due date, weeks pregnant calculator, pregnancy weeks, baby due date. Whether you need a quick result or are working through a longer project, the tool handles all common variations without any configuration.
Why use Allio Tools's Pregnancy Due Date Calculator?
All calculations run locally. No personal health data is ever transmitted or stored anywhere. The tool is completely free with no usage limits, no premium tiers, and no account required. Available in 11 languages and optimised for all screen sizes, the Pregnancy Due Date Calculator works on desktop, tablet, and mobile with no app download needed.
See also:BMI Calculator · TDEE Calculator · Calorie Calculator
How the Pregnancy Due Date Calculator works
Enter the first day of your last menstrual period (LMP) in the date field.
Click Calculate Due Date to see your estimated due date (EDD), how many weeks and days pregnant you are, current trimester, and days remaining.
View the trimester breakdown below, with your current trimester highlighted.
Tips & tricks
- There's only one input — the first day of your last menstrual period. There's no separate conception-date entry or cycle-length adjustment.
- The due date always assumes a standard 28-day cycle (Naegele's Rule); it doesn't personalize for longer or shorter cycles.
- Beyond the three trimester ranges and a running days-left countdown, there's no week-by-week development timeline or list of other specific milestone dates.
Frequently Asked Questions
How is the due date calculated?
The standard method (Naegele's Rule) adds 280 days (40 weeks) to the first day of your last menstrual period. This assumes a 28-day cycle with ovulation on day 14. Most pregnancies deliver within 2 weeks of the calculated date.
Can I calculate my due date from my conception date instead of LMP?
No — there's only one date field, and it's specifically for the first day of your last menstrual period. If you only know your conception date, add roughly 2 weeks to approximate your LMP date before entering it.
Can I adjust for a cycle length other than 28 days?
No — there's no cycle-length input. The calculation always assumes a standard 28-day cycle (280 days from LMP to due date). If your cycles are longer or shorter, the estimate may be less accurate for you.
What are the three trimesters?
First trimester: weeks 1–12. Second trimester: weeks 13–26. Third trimester: weeks 27–40. The tool shows all three with your current one highlighted.
Does the tool show week-by-week development milestones or a due-date countdown for other milestones (like the anatomy scan)?
No — beyond the three trimester ranges and a running "days left" count to your due date, there's no week-by-week fetal development timeline or specific milestone-date breakdown (like end-of-first-trimester or full-term dates).
Is my data safe when using the Pregnancy Due Date Calculator?
Completely safe. The Pregnancy Due Date Calculator processes everything locally in your browser. No input data, results, or usage information is ever transmitted to or stored on any server.
How accurate are the Pregnancy Due Date Calculator calculations?
The Pregnancy Due Date Calculator uses clinically validated formulas such as the Mifflin–St Jeor or Harris–Benedict equations where applicable. Results are population-based estimates and can differ from measured values by 10–20% for individuals with atypical body composition. See our <a href="/methodology/">Methodology page</a> for full formula sources and references. Consult a qualified healthcare professional before making medical or dietary decisions.
Which formula does the Pregnancy Due Date Calculator use?
The Pregnancy Due Date Calculator uses an established, peer-reviewed formula endorsed by leading health organisations such as the WHO, CDC, or NIH where applicable. The specific formula is chosen for its validated accuracy across diverse adult populations under normal conditions.
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