How to Use the Due Date Calculator

1. Enter the first day of your last menstrual period (LMP).
2. Click Calculate Due Date.
3. The tool adds 280 days (40 weeks) to your LMP and displays your estimated due date.

This calculator is helpful for anyone wanting to quickly figure out:

• “When is my due date?”
• “How far along am I based on LMP?”
• “What is 40 weeks from my last period?”

Everything is based on simple date math.

FAQ

How is the due date calculated?

The calculator adds 280 days (40 weeks) to the first day of your LMP. This is the standard method used for estimating due dates using date math.

Is this the same as a pregnancy week calculator?

Not exactly. This tool estimates your due date, while a pregnancy week calculator tells you how many weeks pregnant you are today. Both use the same LMP based math.

What if my cycle is not 28 days?

This calculator uses the standard 28 day cycle assumption because it’s the universal baseline for due date math. It does not adjust for cycle variations.

Does this give a medically verified due date?

No — this is a date math calculator only, not medical advice. It simply adds 280 days to your LMP.

Can I use this to plan pregnancy timelines?

Yes. Many people use this tool for:

• “due date from LMP”
• “pregnancy timeline calculator”
• “40 week due date estimate”

It’s a fast way to map out important pregnancy dates using simple math.