Pregnancy Weight Gain by Week Calculator
Expected weight gain range by gestational week.
Enter your values
Choose one of: Underweight (<18.5), Normal (18.5-24.9), Overweight (25-29.9), Obese (30+).
Enter the current week in weeks.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Suggested gain to date
- 5.6 - 8 kg
- Total recommended by term
- 11.5 - 16 kg
- Current week
- 24 weeks
Quick answer
Recommended pregnancy weight gain depends on pre-pregnancy BMI category and gestational week, per IOM guidelines.
IOM total gain ranges by BMI category, distributed across trimesters
At a glance
| What it does | Expected weight gain range by gestational week. |
|---|---|
| Category | Health |
| Inputs needed | Pre-pregnancy BMI category, Current week |
| Main output | Suggested gain to date |
| Formula | IOM total gain ranges by BMI category, distributed across trimesters |
| Cost | Free — no sign-up, no download |
How to use the Pregnancy Weight Gain by Week Calculator
- 1Select your pre-pregnancy BMI category and enter your current week of pregnancy.
- 2The ranges follow US Institute of Medicine guidelines and are population averages.
- 3This is general guidance only — always follow the specific advice of your obstetric care provider.
Inputs explained
- Pre-pregnancy BMI category
- Choose one of: Underweight (<18.5), Normal (18.5-24.9), Overweight (25-29.9), Obese (30+).
- Current week(weeks)
- Enter the current week in weeks.
Worked example
Using the values the calculator loads with:
Inputs
- Pre-pregnancy BMI categoryNormal (18.5-24.9)
- Current week24 weeks
Results
- Suggested gain to date5.6 - 8 kg
- Total recommended by term11.5 - 16 kg
- Current week24 weeks
Frequently asked questions
What if I'm gaining faster or slower?
Some variation is normal, but discuss significant deviations with your midwife or doctor.
Does twin pregnancy change this?
Yes, multiples have higher recommended gain ranges not covered by this tool.
What do I need to enter into the Pregnancy Weight Gain by Week Calculator?
Just 2 values: pre-pregnancy bmi category, current week. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Pregnancy Weight Gain by Week Calculator work out the answer?
Recommended pregnancy weight gain depends on pre-pregnancy BMI category and gestational week, per IOM guidelines. It applies the formula IOM total gain ranges by BMI category, distributed across trimesters and shows the working so you can check each step by hand.
Is the Pregnancy Weight Gain by Week Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.