hCG Doubling Time Calculator

Normal hCG Doubling in Early Pregnancy

In a healthy intrauterine pregnancy below ~6 weeks gestation, serum beta-hCG typically doubles every 48–72 hours. After hCG passes ~1,200 mIU/mL, doubling time slows to ~72–96 hours, and beyond 6,000 mIU/mL it can take 96+ hours to double.

Reference Values

• 3 weeks — 5–50 mIU/mL
• 4 weeks — 5–426
• 5 weeks — 19–7,340
• 6 weeks — 1,080–56,500
• 7–8 weeks — 7,650–229,000
• 9–12 weeks — 25,700–288,000
• Peak (~10 wks) — up to 290,000

Clinical Interpretation

Doubling times longer than 72 hours, or hCG rises less than 53% over 48 hours, are associated with non-viable or ectopic pregnancy. However, a single suboptimal rise does not confirm pregnancy failure — ultrasound and serial values are needed. Falling levels usually indicate miscarriage or ectopic.