EZ1 Calculators
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Due Date Calculator

Calculate your Estimated Due Date instantly and free by entering your Last Menstrual Period.

  • Free
  • No sign-up
  • Instant results

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How to use it

  1. Enter the first day of your last menstrual period (LMP) in the calendar
  2. Click the Calculate button
  3. Read the Estimated Due Date displayed

What it does – The Due Date Calculator adds 280 days (40 weeks) to the first day of your last menstrual period to give you an Estimated Due Date. Why it matters – Knowing the due date helps you schedule prenatal appointments, plan maternity leave, and prepare for baby‑related purchases. How to read it – The result shows a single calendar date; that is the day your pregnancy is expected to reach full term. It’s a guideline, not a guarantee, and actual delivery can occur a week earlier or later. Use the date to set reminders, discuss timing with your provider, and keep a realistic timeline for your pregnancy journey.

Pro tips

  • Allow a few days for rounding; the calculator uses whole days, so the due date may shift by one day.
  • If you’re unsure of the exact LMP, use the first day you recall bleeding started.
  • Print or save the result early to avoid losing it when you revisit the site.
  • Remember the due date is an estimate; doctors may adjust it based on ultrasounds.

Real-life examples

  • A first‑time mom wants to know when to start her maternity leave paperwork.
  • A couple is planning a baby shower and needs a target date for invitations.
  • A healthcare provider needs a quick reference for a patient’s expected delivery date.

Case study

Emily entered her LMP of March 3, 2024, and instantly saw an estimated due date of December 8, 2024. She used the date to book her 36‑week scan, order a hospital bag, and inform her employer, giving her peace of mind and a clear timeline.

Frequently asked questions

How is the due date calculated?
The calculator adds 280 days (40 weeks) to the first day of your last menstrual period, following Naegele’s rule.
Can I use the calculator if I don’t know my exact LMP?
Use the first day you remember bleeding; the estimate will still be useful, though less precise.
Why might my actual delivery differ from the estimated date?
Full‑term births naturally vary by a week earlier or later, and medical factors can shift the date.
Do I need to sign up to get the result?
No, the calculation is instant, free, and requires no registration.
Is the calculator reliable for multiple pregnancies?
Yes, the same 280‑day rule applies, but discuss any differences with your provider.