Online Calculator

Pregnancy Weight Gain Calculator

The IOM publishes gain ranges keyed to starting BMI. Locate yourself at your current week — single or twin pregnancy.

Recommended gain by week 20

1.8–17.5 kg

Total pregnancy range
25–35 lb
Pre-pregnancy BMI
25

Ranges are guidance — obstetrician advice always wins.

How the Pregnancy Weight Gain Calculator works

The calculation follows the standard method used across the US — no shortcuts, no hidden assumptions. Here is exactly what happens behind the scenes:

Frequently Asked Questions

How does the Pregnancy Weight Gain Calculator work?

Enter your numbers above and results update instantly using standard formulas, computed entirely on your device.

Is the Pregnancy Weight Gain Calculator free to use?

Yes — completely free with no signup required, and it works on phones, tablets, and desktops.