Pregnancy Weight Gain Calculator

Calculate healthy weight gain during pregnancy based on your pre-pregnancy BMI. Get personalized recommendations for total weight gain and weekly targets throughout your pregnancy.

Your Information

Enter height in centimeters

Your weight before pregnancy in kilograms

Your current weight to track progress

How many weeks pregnant are you?

Weight Gain Recommendations

Pre-pregnancy BMI
23.9
Normal Weight
Recommended Total Weight Gain
11.5-16.0 kg
kilograms for entire pregnancy
Weekly Weight Gain (2nd & 3rd Trimester)
0.3-0.5 kg
kg per week after week 12
Target Weight at Delivery
76.5-81.0 kg
kilograms at 40 weeks

Weight Gain by Trimester

First Trimester (Weeks 1-12)

Expected gain: 1-2 kg

Rate: 1-2 kg total

Many women gain little to no weight in the first trimester due to morning sickness. This is normal.

Second Trimester (Weeks 13-26)

Expected gain: 4.6-6.4 kg

Rate: 0.3-0.5 kg per week

Steady weight gain begins as appetite returns and baby grows rapidly.

Third Trimester (Weeks 27-40)

Expected gain: 4.6-6.4 kg

Rate: 0.3-0.5 kg per week

Continued steady gain as baby reaches full size and birth weight.

Weight Gain Guidelines by BMI Category

BMI CategoryBMI RangeSingle BabyTwins
UnderweightBelow 18.512.5-18 kg17-25 kg
Normal Weight18.5-24.911.5-16 kg17-25 kg
Overweight25.0-29.97-11.5 kg14-23 kg
Obese30.0 and above5-9 kg11-19 kg

Understanding Healthy Weight Gain

Why Weight Gain Matters

  • Supports baby's growth and development
  • Provides energy for breastfeeding
  • Helps prevent complications
  • Supports maternal health

Where the Weight Goes

• Baby: 3-4 kg (6.5-8 lbs)

• Placenta: 0.7 kg (1.5 lbs)

• Amniotic fluid: 0.9 kg (2 lbs)

• Breast tissue: 0.9 kg (2 lbs)

• Blood volume: 1.8 kg (4 lbs)

• Fat stores: 2.7-3.6 kg (6-8 lbs)

• Uterus: 0.9 kg (2 lbs)

Risks of Inadequate Gain

  • Low birth weight baby
  • Preterm delivery
  • Developmental issues
  • Breastfeeding difficulties

Risks of Excessive Gain

  • Gestational diabetes
  • High blood pressure
  • Large baby (macrosomia)
  • Difficult delivery
  • Postpartum weight retention

Tips for Healthy Weight Gain

Nutrition Guidelines

  • Eat nutrient-dense foods
  • Include protein at every meal
  • Choose whole grains over refined
  • Eat plenty of fruits and vegetables
  • Stay hydrated with water
  • Take prenatal vitamins
  • Limit empty calories from sweets

Activity Guidelines

  • Stay active with approved exercises
  • Walk regularly if possible
  • Do prenatal yoga or swimming
  • Avoid high-impact activities
  • Listen to your body
  • Get adequate rest
  • Manage stress levels

Example Calculation

Woman: 5'6" (168 cm), Pre-pregnancy weight: 140 lbs (63.5 kg)

Calculation Steps:

1. Calculate BMI: 140 ÷ (66²) × 703 = 22.6

2. BMI Category: Normal weight (18.5-24.9)

3. Recommended gain: 25-35 lbs (11.5-16 kg)

4. Weekly gain (2nd/3rd trimester): 0.8-1 lb/week

Target Weights:

• At 20 weeks: 148-152 lbs (67-69 kg)

• At 30 weeks: 156-162 lbs (71-73.5 kg)

• At delivery: 165-175 lbs (75-79.5 kg)

• First trimester gain: 2-4 lbs (1-2 kg)

Frequently Asked Questions

What if I'm gaining weight too quickly?

Consult your healthcare provider. They may recommend dietary changes, monitoring for gestational diabetes, or adjusting your activity level. Don't try to lose weight during pregnancy.

What if I'm not gaining enough weight?

Your doctor may recommend increasing caloric intake with nutrient-dense foods, addressing any underlying issues like morning sickness, or monitoring baby's growth more closely.

How often should I weigh myself?

Weekly weigh-ins at the same time of day are sufficient. Daily fluctuations are normal and can be misleading. Focus on overall trends rather than day-to-day changes.