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
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 Category | BMI Range | Single Baby | Twins |
---|---|---|---|
Underweight | Below 18.5 | 12.5-18 kg | 17-25 kg |
Normal Weight | 18.5-24.9 | 11.5-16 kg | 17-25 kg |
Overweight | 25.0-29.9 | 7-11.5 kg | 14-23 kg |
Obese | 30.0 and above | 5-9 kg | 11-19 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.
Related Calculators
Pregnancy Calculator
Calculate due date and pregnancy timeline
BMI Calculator
Calculate your Body Mass Index
Calorie Calculator
Calculate daily calorie needs during pregnancy
Ideal Weight Calculator
Find your ideal pre-pregnancy weight
BMR Calculator
Calculate your Basal Metabolic Rate
Body Fat Calculator
Calculate body fat percentage