Calculators/pregnancy calculator

Pregnancy Calculator

Estimate gestational age, due date, trimester, and key dates from your last menstrual period. These results are estimates and should be confirmed with a healthcare professional, especially if you have irregular cycles or uncertain dates.

Inputs

First day of last period (LMP)

Average cycle length (optional)

Used for a simple adjustment vs a 28-day cycle.

days

Pregnancy timeline

Gestational age (today)0w 0d

Trimester1st trimester

Estimated conceptionJan 29, 2026

Estimated due dateOct 22, 2026

Days until due date279

Cycle length used: 28 days. Progress: 0%.

Estimates only. Confirm dating and care guidance with a healthcare professional.

How to use it

Enter the first day of your last period (LMP).
Optionally enter your average cycle length for a rough adjustment.
Review gestational age, trimester, estimated conception date, and due date.
Use the timeline as a planning reference—not a medical diagnosis.

Key formulas

Gestational age (estimate): Gestational age ≈ today − LMP
Due date (rule of thumb): EDD ≈ LMP + 280 days (+ adjustment for cycle length)

FAQ

Gestational age is typically counted from the first day of the last menstrual period (LMP), which is about 2 weeks before ovulation in a 28‑day cycle.

Ovulation timing varies and many people don’t ovulate exactly on day 14. The conception estimate is a rough approximation.

Definitions vary. A common split is: 1st trimester up to week 13, 2nd trimester weeks 14–27, 3rd trimester week 28 to delivery.

Often, especially early in pregnancy. Providers may adjust due date estimates based on ultrasound measurements and clinical context.

No. Use this as a planning estimate and consult a healthcare professional for dating and medical guidance.