Pregnancy Due Date Calculator
This tool estimates an expected due date and maps key milestones across pregnancy using standard obstetric dating methods. It’s helpful for planning prenatal appointments, organizing leave and childcare, and following trimester progress with a clear week-by-week timeline.
The Pregnancy Due Date Calculator gives us a reliable calendar anchor so we can schedule care, prepare for each stage, and share an easy-to-understand plan with partners or providers. The goal is to replace guesswork with a practical timeline—while remembering that every pregnancy is unique and clinical guidance ultimately comes from your healthcare professional.
Estimate your due date from LMP, conception, or ultrasound and view your current gestational age, trimester, and key milestone dates.
Your details for due date calculation
Heads-up: This is educational planning info only—always follow your clinician’s guidance.
Pregnancy timeline
Results interpretation: who this helps
- Expecting parents: quick planning for leave, travel, and registries.
- Care coordinators: align appointments around common milestones.
- Educators: simple, transparent dating math for classroom demos.
Use cases & examples
Example 1 — LMP method: LMP 04-10-2025, cycle 30 days → adjust by +2 days: EDD ≈ 01-16-2026.
Example 2 — Known conception: Conception 05-01-2025 → EDD ≈ 01-22-2026.
Example 3 — Ultrasound dating: Scan 08-15-2025 at 12w3d → remaining 280−87 = 193 days → EDD ≈ 02-24-2026.
Pregnancy Due Date — FAQ
Which method should I use to estimate my due date?
Use ultrasound if you have an early scan with a reported gestational age. Otherwise, use LMP (with your average cycle length) or a known conception date.
How accurate is an ultrasound due date?
Early ultrasounds (first trimester) are typically most precise. Later scans can vary more because fetal size has a wider normal range.
What if my cycle isn’t 28 days?
We adjust LMP-based EDD by (cycle length − 28) days. Longer cycles shift EDD later; shorter cycles shift EDD earlier.
Why does conception use 266 days?
Gestational age counts from LMP, about two weeks before ovulation. Conception-based EDD therefore adds 266 days instead of 280.
What does gestational age mean?
It’s the length of pregnancy measured from the LMP-equivalent start date. We show it in weeks and days as of today.
What are typical trimester boundaries?
First: through 13 weeks 6 days, Second: 14–27 weeks 6 days, Third: 28 weeks and beyond.
Why is my due date different after a new scan?
Ultrasound dating can refine the timeline. Many care teams pivot to the earliest reliable ultrasound estimate.
Is this medical advice?
No. This is for education and planning only. Always follow your clinician’s guidance for diagnosis and care.
Due date basics: methods, accuracy, and planning around milestones
We designed our due date estimator to keep the math transparent. Whether we start from the last menstrual period, a known conception, or an ultrasound, the goal is the same: give a clear, shareable timeline.
Which dating method is most accurate?
Early ultrasound is often considered most precise. LMP can be accurate with regular cycles, especially when adjusted for cycle length. A documented conception date (e.g., IVF) can be exact.
Understanding trimesters and terms
We show common planning markers—end of first trimester (~12 weeks), detailed anatomy scan (~20 weeks), and term windows (37 to 42 weeks). These are guides; your clinician’s advice comes first.
Using the timeline for real life
Families and teams use the timeline to queue appointments, travel, and leave. The copyable link keeps everyone synced if plans change after a new scan.