Pregnancy Due Date Calculator

Estimate pregnancy due date from the first day of the last menstrual period.

Formula

Estimated due date = first day of last menstrual period + 280 days.

LMP on Jan 1 gives an estimated due date around Oct 8.

Enter the requested values, then the calculator applies the formula and updates the result instantly.

Use this calculator for quick planning, estimates, comparisons, and everyday decisions where the formula applies.

Common mistakes include using inconsistent units, entering percentages as decimals, rounding too early, or forgetting extra allowances such as waste, tax, or fees.

Examples

Example

LMP on Jan 1 gives an estimated due date around Oct 8.

Use the calculator above for your own numbers.

Formula Check

Estimated due date = first day of last menstrual period + 280 days.

Formula-based result

Practical Use

Estimate pregnancy due date from the first day of the last menstrual period.

Fast online calculation

How to Calculate Pregnancy Due Date Manually

Start with the values requested in the form, keep the units consistent, and apply this formula: Estimated due date = first day of last menstrual period + 280 days.

The calculator above follows the same logic, then formats the answer so you can quickly compare inputs, copy the result, and check the related tools if your task has another step.

When to Use This Calculator

Quickly estimate a result before making a decision
Compare options using the same formula
Check manual calculations
Save time on repeated calculations

How It Works

Enter your values.
The page applies the formula.
Review the main result, details, and formula used.

Common Mistakes

Mixing different units
Using the wrong percentage format
Leaving required fields blank
Rounding before the final step

Related Calculators

DDBDue Date by Last Period CalculatorEstimate due date using last period date and cycle length.

Frequently Asked Questions

What does the Pregnancy Due Date Calculator do?

Estimate pregnancy due date from the first day of the last menstrual period.

Is this result an estimate?

Yes. The calculator follows the formula shown on the page. Verify important decisions with a qualified professional where needed.

Can I use this on mobile?

Yes. The calculator is designed to work on phones, tablets, and desktop screens.