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Pregnancy Due Date Calculator

Health & Body

Due date, gestational week and trimesters

Quick Answer

Pregnancy Due Date Calculator: Due date, gestational week and trimesters. Due date = first day of last period + 280 days (40 weeks).

Estimated due date

May 23, 2027

Steps (Naegele’s rule)

  1. 1Baseline: LMP + 280 days (40 weeks, 28-day cycle)
  2. 228-day cycle: no adjustment
  3. 3Due date = May 23, 2027

Key prenatal checkups

WeeksCheckup
Wk 6-8Ultrasound: confirm intrauterine & heartbeat
Wk 11-13+6NT scan
Wk 15-20Down syndrome screening / NIPT
Wk 20-24Anatomy scan
Wk 24-28OGTT glucose test
Wk 30-32Growth scan & position
Wk 36+Weekly visits & NST

💡 Only ~5% of babies arrive exactly on the due date — full-term range is week 37-42. Early ultrasound dating (wk 8-13) is more accurate than LMP; your OB may adjust the date after the first scan.

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How to Use

  1. Enter body metrics: fill height, weight, age etc. as prompted by the Pregnancy Due Date Calculator.
  2. Read value and grade: results appear instantly with an authority-based classification.
  3. Check reference tables: confirm your range and healthy targets against the tables on this page.
  4. Back-solve your goal: adjust inputs to see what it takes to reach a target.

Key Points

  • Pregnancy Due Date Calculator is a free online health tool — open and use, no sign-up.
  • All calculations run locally in your browser; your data never leaves the device.
  • Key capability: Due date, gestational week and trimesters.
  • Results come with formulas and reference tables so you can verify every number.

Formula & How It Works

Naegele's rule

Due date = first day of last period + 280 days (40 weeks)
Trimesters: 1–13w / 14–27w / 28–40w

FAQ

How do I use the Pregnancy Due Date Calculator?
Open the page and fill in the input fields — results update automatically. Due date, gestational week and trimesters.
Are the results accurate?
Results follow published international standards (WHO, ACE, IOM) and are for reference only.
Can this replace medical advice?
No. Always consult a qualified healthcare professional for health decisions.
Is it free? Do I need to sign up?
Completely free. No registration, login or download required.
Does it work on mobile?
Yes. The responsive design works on all devices.

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Source & Updates

Based on WHO, ACE, IOM and other published international standards. Last updated: 2025-07

Authoritative sources:

Last updated:

Formulas and content on this page are reviewed by the YiJianSuan team. For reference only — official sources prevail.

Maintained and periodically reviewed by the YiJianSuan editorial team — review process in ourEditorial Policy.

Cite this page: YiJianSuan. Pregnancy Due Date Calculator[EB/OL]. https://www.yijiansuan.com/en/c/health/due-date

Results provided by this tool are for reference only and do not constitute professional advice.