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Pregnancy Due Date

Calculate expected baby delivery date from last menstrual period.

2026 tax-year compliant日本語版を見る (Japanese)

Note: Input field labels are in Japanese (the calculator engine is shared with the Japanese version). Numeric input works the same way; the results are universal numbers in JPY (¥).

Pregnancy Due Date

Calculate expected baby delivery date from last menstrual period.

Key Points

  • Gestation: 280 days from LMP
  • Trimester 1: 0-13 weeks
  • Trimester 2: 14-26 weeks
  • Trimester 3: 27-40 weeks

FAQ

Same as international standard?

Yes — 280 days from last period (LMP). Naegele's rule.

⚠️ Disclaimer

This calculator provides estimates only. For actual tax filing, please consult a licensed 税理士 (zeirishi) or FP (Financial Planner). Results are not a substitute for professional advice.

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