Calculator Comparison

Due Date Calculator vs Pregnancy Calculator

Not sure which calculator to use? Here's a side-by-side comparison of the Due Date Calculator and Pregnancy Calculator to help you pick the right one for your needs.

Due Date Calculator

Pregnancy & Baby

Calculate your estimated due date using your last menstrual period, conception date, or IVF transfer date.

What you enter

Calculate Based On
Date

What you get

Estimated Due Date(primary)
Estimated Conception Date
Current Week of Pregnancy
Days Until Due Date

Use Due Date Calculator

Pregnancy Calculator

Pregnancy & Baby

Track your pregnancy progress week by week with trimester information and key milestone dates based on your due date.

What you enter

First Day of Last Period
Average Cycle Length

What you get

Current Week(primary)
Estimated Due Date
Current Trimester
Days Remaining

Use Pregnancy Calculator

Key Differences

Feature	Due Date Calculator	Pregnancy Calculator
Category	Pregnancy & Baby	Pregnancy & Baby
Inputs	2 required fields	2 required fields
Outputs	4 results	4 results
Chart	No chart	No chart
FAQs	3 answered	3 answered

Input Comparison

Only in Due Date Calculator

Calculate Based On
Date
Average Cycle Length (for LMP)

Only in Pregnancy Calculator

First Day of Last Period
Average Cycle Length

Which Calculator Should You Use?

Use the Due Date Calculator if you need to:

Calculate estimated due date
When you know your calculate based on and date

Use the Pregnancy Calculator if you need to:

Calculate current week
When you know your first day of last period and average cycle length

Frequently Asked Questions

How is the due date calculated?

The most common method (Naegele's rule) adds 280 days (40 weeks) to the first day of your last menstrual period. Adjustments are made for cycle lengths that differ from 28 days.

How accurate is a due date?

Only about 5% of babies are born on their exact due date. Most babies arrive within 2 weeks before or after the due date. First-time mothers tend to deliver slightly later.

How long is a pregnancy?

A full-term pregnancy is about 40 weeks (280 days) from the first day of your last menstrual period (LMP). Most babies are born between 38 and 42 weeks.

How are pregnancy weeks counted?

Pregnancy weeks are counted from the first day of your last menstrual period, not from conception. Conception typically occurs around week 2. So at 4 weeks pregnant, the embryo is about 2 weeks old.

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Bottom Line

Choose the Due Date Calculator if you need to calculate estimated due date. Use the Pregnancy Calculator if you need to calculate current week. Both calculators are free and require no sign-up.

Use Due Date Calculator Use Pregnancy Calculator

Feature

Due Date Calculator

Pregnancy Calculator