Pregnancy Tools
Due Date Calculator — Estimated Delivery Date
Estimate baby due date from last period or conception date using Naegele-style calendar math. Free, educational, not medical advice.
TL;DR: Choose LMP or conception date; the tool adds 280 days (LMP) or 266 days (conception) to show your estimated due date, current week (1–40), and trimester end dates.
Reviewed by FYN Tools Editorial · Guides ·
Privacy & processing: EDD is an estimate — only about 5% of babies arrive on the exact date. Confirm with prenatal care.
Pregnancy Due Date Calculator
Estimate baby due date from last period or conception date using Naegele-style calendar math. Free, educational, not medical advice.
- Inputs
- Last menstrual period (LMP) date OR conception date — toggle with the mode buttons
- Outputs
- Estimated due date, current pregnancy week, trimester 1 and 2 end dates
- Processing
- Client-side (browser)
- Limits
- Calendar estimate only — ultrasound dating may differ; not medical advice
Quick steps
- Tap Use Last Period (LMP) or Use Conception Date.
- Pick the date from the calendar picker.
- Read the estimated due date and current pregnancy week.
- Note trimester 1 and 2 end dates for planning discussions.
- Share the estimate with your prenatal clinician — they may adjust after ultrasound.
- LMP or conception date modes
- 280-day / 266-day calendar math
- Current pregnancy week (1–40)
- Trimester 1 and 2 end dates
- Medical disclaimer on page
Data input / output
| Inputs | Last menstrual period (LMP) date OR conception date — toggle with the mode buttons |
|---|---|
| Outputs | Estimated due date, current pregnancy week, trimester 1 and 2 end dates |
| Formats | Calendar date picker |
| Limits | Calendar estimate only — ultrasound dating may differ; not medical advice |
| Processing | Client-side (browser) |
How to Use the Pregnancy Due Date Calculator
- Tap Use Last Period (LMP) or Use Conception Date.
- Pick the date from the calendar picker.
- Read the estimated due date and current pregnancy week.
- Note trimester 1 and 2 end dates for planning discussions.
- Share the estimate with your prenatal clinician — they may adjust after ultrasound.
What is a Pregnancy Due Date Calculator?
Pregnancy Due Date Calculator on FYN Tools calculate your baby due date using LMP or conception date. Use the tool above — free, no account required.
Calendar and symptom tools vary by person. Use output for planning and prenatal discussions — not as diagnosis or emergency guidance.
Calculate your baby due date using LMP or conception date.
How it works
In LMP mode the tool adds 280 days to your last period start (Naegele rule). In conception mode it adds 266 days. It also calculates weeks pregnant from today and trimester boundary dates.
Explore more tools on our site.
Common Use Cases & Examples
- First prenatal visit prep: Bring an LMP-based EDD to your booking appointment before ultrasound dating.
- Partner planning: See trimester end dates when scheduling travel or leave.
- IVF or known conception: Switch to conception mode when you know the transfer or conception date.
Input / Output Examples
Input
LMP: January 15, 2026
Output
Estimated due date ~October 22, 2026; current week shown from today's date
Input
Conception date: April 1, 2026
Output
Estimated due date ~December 22, 2026 (266-day method)
Frequently Asked Questions
Is the due date calculation exact?+
It provides a reliable estimate based on standard pregnancy timelines. Actual delivery may vary.
What if I know my conception date?+
Select the conception option to calculate a due date based on that date.
Does this replace medical advice?+
No. Always confirm due dates with your healthcare provider.
Is my data saved?+
No. All calculations happen in your browser.
Key Features
- LMP or conception date modes
- 280-day / 266-day calendar math
- Current pregnancy week (1–40)
- Trimester 1 and 2 end dates
- Medical disclaimer on page
Benefits
Free access with no signup for core features
Fast browser-based processing
Mobile-friendly layout
When to Use Pregnancy Due Date Calculator
- When you need to calculate your baby due date using lmp or conception date
- Before a prenatal or women's health visit — screenshot or export your log
- On mobile for quick tracking without installing an app
Advantages
- Free access with no signup for core features
- Fast browser-based processing
- Mobile-friendly layout
- Clear how-to steps and FAQs on the same page
Tips
- Double-check units (currency, dates, measurements) before acting on results.
- Use a modern browser for best performance with canvas and file uploads.
- Contact a clinician if symptoms are severe or unusual — online tools cannot triage emergencies.
Common Mistakes
Using calendar predictions as contraception without clinician guidance
Ignoring severe symptoms because an app log looks normal
Expecting cloud backup when data is stored only in this browser
Summary
Use Pregnancy Due Date Calculator above, then browse related pregnancy tools linked below.