Pregnancy Due Date Calculator

Calculate your pregnancy due date, conception date, and current pregnancy week. Choose from three calculation methods: last menstrual period (LMP), conception date, or known due date. Get detailed trimester breakdowns, week-by-week tracking, and important pregnancy milestones. See how far along you are with a visual progress tracker.

Pregnancy Calculator: Calculate your due date, conception date, and current pregnancy week. Choose your calculation method and get a week-by-week breakdown of your pregnancy journey.

This is the first day of your last period before you became pregnant

How It Works

1. Choose Calculation Method

Select how you want to calculate: from last menstrual period (LMP), conception date, or due date. LMP is most common and what doctors typically use.

2. Enter Your Date

Input the first day of your last period, conception date, or your known due date. The calculator uses standard 40-week (280 day) pregnancy timeline.

3. View Your Results

See your due date, estimated conception date, current pregnancy week, and trimester. Includes a progress bar showing how far along you are.

4. Track Your Journey

Review trimester information, key milestones, and important pregnancy tips. Get a week-by-week breakdown of your pregnancy timeline.

Examples

Example 1: Calculate from Last Period

Method: Last Menstrual Period (LMP) LMP Date: March 1, 2025 Results: Due Date: December 6, 2025 Conception Date: March 15, 2025 (estimated) Current Week: 14 weeks (as of June 7, 2025) Trimester: 2nd trimester Days Pregnant: 98 days Weeks Remaining: 26 weeks Standard calculation - most accurate method used by doctors.

Example 2: Calculate from Conception

Method: Conception Date Conception Date: April 10, 2025 Results: Due Date: January 1, 2026 LMP (calculated): March 27, 2025 Current Week: 8 weeks (as of June 7, 2025) Trimester: 1st trimester Days Pregnant: 58 days Weeks Remaining: 32 weeks If you know when conception occurred (IVF, tracked ovulation, etc.)

Example 3: Working Backwards from Due Date

Method: Due Date Due Date: November 15, 2025 (from ultrasound) Results: LMP (calculated): February 8, 2025 Conception Date: February 22, 2025 (estimated) Current Week: 17 weeks (as of June 7, 2025) Trimester: 2nd trimester Days Pregnant: 119 days When your doctor has given you a due date based on ultrasound measurements.

Frequently Asked Questions

How is pregnancy due date calculated?

Due date is calculated as 280 days (40 weeks) from the first day of your last menstrual period (LMP). This is called Naegele's Rule. The calculation assumes: (1) regular 28-day menstrual cycles, (2) ovulation on day 14, and (3) conception shortly after ovulation. Your doctor may adjust this based on ultrasound measurements, which can be more accurate, especially in the first trimester.

Why is pregnancy calculated from last period, not conception?

Pregnancy is dated from the first day of your last menstrual period (LMP) because: (1) Most women can remember when their last period started, (2) Exact conception date is often unknown, (3) This method has been the medical standard for decades. Even though conception occurs about 2 weeks after LMP, you are considered "2 weeks pregnant" at conception. A full-term pregnancy is 38 weeks from conception but 40 weeks from LMP.

How accurate is the pregnancy due date calculator?

Pregnancy calculators provide estimates - only about 5% of babies are born on their exact due date. Most babies (80%) are born within 2 weeks before or after the due date (38-42 weeks). Accuracy depends on: (1) Regular menstrual cycles (28 days), (2) Knowing exact LMP date, (3) No fertility treatments. First trimester ultrasounds (before 13 weeks) are more accurate and can adjust the due date by a few days.

What are the three trimesters of pregnancy?

Pregnancy is divided into three trimesters: (1) First Trimester (Weeks 1-12): Embryo develops major organs, heart starts beating, morning sickness common, highest miscarriage risk. (2) Second Trimester (Weeks 13-26): "Honeymoon period" with more energy, feel baby move, find out sex, anatomy scan at 20 weeks. (3) Third Trimester (Weeks 27-40): Rapid growth, baby gains most weight, practice contractions, prepare for birth.

When will I feel my baby move?

First-time mothers typically feel baby movements (called "quickening") between 18-25 weeks, with 20 weeks being average. Women who have been pregnant before often feel movement earlier, around 16-18 weeks, because they recognize the sensation. Early movements feel like flutters, bubbles, or butterflies. By 24-28 weeks, movements become stronger kicks and jabs. Contact your doctor if you notice decreased fetal movement in the third trimester.