Pregnancy Month Calculator

Free Pregnancy Month Calculator

Use this free pregnancy month calculator to instantly find out which of the ten pregnancy months you're currently in, how many weeks and days remain before the next one starts, and the exact estimated date range for every month of your pregnancy.

Pregnancy is traditionally divided into ten lunar months of four weeks each, rather than the more familiar nine calendar months. This calculator lays out that full month-by-month timeline based on either your last menstrual period or your known due date.

How to Use the Pregnancy Month Calculator

• Choose whether you know your last menstrual period or your due date.
• Select the relevant date.
• Click Calculate My Month.
• View your current month, remaining weeks, and the full month-by-month timeline instantly.

Features

• Works from either your last menstrual period or a known due date.
• Shows exactly how many weeks and days remain in your current pregnancy month.
• Lays out the estimated date range for all ten pregnancy months, not just your current one.
• Mobile-friendly with print, share, copy, and download options.

Frequently Asked Questions

How many months is a pregnancy?

Pregnancy is commonly said to last nine months, but by the traditional lunar calendar used in most due-date calculations, it actually spans ten months of four weeks each, for a total of forty weeks.

How is my current pregnancy month calculated?

This calculator counts your pregnancy from the first day of your last menstrual period, or works backward from your due date if that's what you entered, then divides the weeks so far into four-week months.

Why does this differ from the usual nine months?

The nine-month figure comes from counting by regular calendar months, while the ten-month figure comes from counting by four-week lunar months. Both describe the same forty-week pregnancy, just measured differently.

Is this calculator free?

Yes, this pregnancy month calculator is completely free to use with no sign-up required.

Method and Sources

This calculator counts pregnancy from the first day of the last menstrual period (LMP) and divides the standard 40-week pregnancy into ten 4-week months. If you enter a due date instead, it works backward 280 days to find the equivalent LMP.

Research that followed pregnancies with precisely measured ovulation dates found that natural pregnancy length can vary by as much as five weeks, even between healthy pregnancies. That is why any calculated date is an estimate, not a prediction of the exact day.

Month-by-month divisions are a convenient way to describe pregnancy, but clinicians track pregnancy in weeks and days. Ultrasound dating may give a different due date from an LMP-based estimate.

Sources:

• American College of Obstetricians and Gynecologists (ACOG) — Committee Opinion No. 700: Methods for Estimating the Due Date
• Jukic AM, Baird DD, Weinberg CR, et al. Length of human pregnancy and contributors to its natural variation. Human Reproduction, 2013

This calculator is for general information only and is not medical advice. Read our Calculation Methodology and medical disclaimer.

Related Calculators

Want to know your trimester instead of your month? Try our pregnancy trimester calculator. Need your exact week? Use the pregnancy week calculator. Need to estimate your due date from scratch? Use the pregnancy due date calculator. Not sure when you conceived? Check the conception date calculator. Want a live countdown to your due date? Use the countdown timer. Curious about your baby's age after birth? See the baby age calculator.