Pregnancy Due Date Calculator
Enter your LMP or conception date to estimate due date.
LMP-based: EDD = LMP + 280 days (40 weeks) [adjust + (Cycle - 28) days]
Conception-based: EDD = Conception + 266 days (38 weeks)
Trimester markers are approximate (e.g., ~12 & ~28 weeks)
LMP: 2026-02-01 -> EDD ~= 2026-11-08 (assuming 28-day cycle).
How is EDD determined?
Naegele rule: EDD = LMP + 280 days (40 weeks). Conception-based method: EDD = Conception + 266 days.
What if my cycle is not 28 days?
We add (Cycle Length - 28) days to the LMP-based estimate to account for longer/shorter cycles.
Is this medical advice?
No. This is an educational tool. Always consult your healthcare provider for personalized timelines.
Why are trimester boundaries approximate?
Trimesters are commonly approximated (e.g., ~12 and ~28 weeks). Providers may use slightly different conventions.
How is due date calculated?
By Naegele rule: EDD = LMP + 280 days (40 weeks). Conception-based adds 266 days.
📐 Formula
LMP-based: EDD = LMP + 280 days (40 weeks) [adjust + (Cycle - 28) days]
Conception-based: EDD = Conception + 266 days (38 weeks)
Trimester markers are approximate (e.g., ~12 & ~28 weeks)
📝 Example Calculation
LMP: 2026-02-01 -> EDD ~= 2026-11-08 (assuming 28-day cycle).
❓ Frequently Asked Questions
How is EDD determined?▼
Naegele rule: EDD = LMP + 280 days (40 weeks). Conception-based method: EDD = Conception + 266 days.
What if my cycle is not 28 days?▼
We add (Cycle Length - 28) days to the LMP-based estimate to account for longer/shorter cycles.
Is this medical advice?▼
No. This is an educational tool. Always consult your healthcare provider for personalized timelines.
Why are trimester boundaries approximate?▼
Trimesters are commonly approximated (e.g., ~12 and ~28 weeks). Providers may use slightly different conventions.
How is due date calculated?▼
By Naegele rule: EDD = LMP + 280 days (40 weeks). Conception-based adds 266 days.