Pregnancy Weight Gain Calculator - Track Healthy Pregnancy Weight

Our free pregnancy weight gain calculator helps you determine the recommended weight gain for your pregnancy based on your pre-pregnancy BMI, current trimester, and whether you’re carrying multiples. Get personalized targets and track your progress for a healthy pregnancy.

What is a Pregnancy Weight Gain Calculator?

A pregnancy weight gain calculator provides personalized weight gain recommendations based on medical guidelines from the Institute of Medicine (IOM) and the American College of Obstetricians and Gynecologists (ACOG). It considers your pre-pregnancy weight, height, and pregnancy stage to determine healthy weight gain ranges.

Why Pregnancy Weight Gain Matters

For Baby’s Health:

Ensures adequate fetal growth and development
Reduces risk of low birth weight (<5.5 lbs)
Prevents macrosomia (baby >9 lbs)
Supports optimal brain development
Provides nutrient reserves for newborn

For Mother’s Health:

Reduces pregnancy complications (gestational diabetes, preeclampsia)
Easier labor and delivery
Faster postpartum recovery
Lower risk of needing C-section
Better long-term health outcomes

Enter Your Information

Recommended Pregnancy Weight Gain

IOM Guidelines by Pre-Pregnancy BMI

The Institute of Medicine provides evidence-based recommendations:

Pre-Pregnancy BMI	Category	Total Weight Gain (Single Baby)	Total Weight Gain (Twins)
< 18.5	Underweight	28-40 lbs (12.7-18.1 kg)	50-62 lbs (22.7-28.1 kg)
18.5-24.9	Normal weight	25-35 lbs (11.3-15.9 kg)	37-54 lbs (16.8-24.5 kg)
25.0-29.9	Overweight	15-25 lbs (6.8-11.3 kg)	31-50 lbs (14.1-22.7 kg)
≥ 30.0	Obese	11-20 lbs (5.0-9.1 kg)	25-42 lbs (11.3-19.1 kg)

Note: These are guidelines for singleton (one baby) pregnancies. Multiples require higher weight gain.

Weight Gain by Trimester

First Trimester (Weeks 1-13):

Typical gain: 1-5 lbs total
Average: 2-4 lbs
Some women lose weight due to morning sickness
Minimal gain is normal and healthy

Second Trimester (Weeks 14-27):

Recommended rate: 1 lb per week (underweight/normal BMI)
Recommended rate: 0.5-0.75 lbs per week (overweight/obese BMI)
Total this trimester: 12-15 lbs (normal BMI)
Steady, consistent gain expected

Third Trimester (Weeks 28-40):

Recommended rate: 1 lb per week (underweight/normal BMI)
Recommended rate: 0.5-0.75 lbs per week (overweight/obese BMI)
Total this trimester: 10-13 lbs (normal BMI)
May plateau in final weeks

Weekly Weight Gain Recommendations

BMI Category	1st Trimester Total	2nd/3rd Trimester Weekly
Underweight	1-5 lbs	1-1.3 lbs/week
Normal weight	1-5 lbs	0.8-1 lb/week
Overweight	1-5 lbs	0.5-0.7 lbs/week
Obese	1-5 lbs	0.4-0.6 lbs/week

Where Does Pregnancy Weight Go?

Distribution of Weight Gain (Normal BMI, 30 lbs Total)

The Baby and Placenta:

Baby: 7-8 lbs (22-26%)
Placenta: 1-2 lbs (3-7%)
Amniotic fluid: 2 lbs (6-7%)
Subtotal: 10-12 lbs

Maternal Tissues:

Uterus enlargement: 2 lbs (6-7%)
Breast tissue: 2 lbs (6-7%)
Blood volume: 3-4 lbs (10-13%)
Body fluids: 3-4 lbs (10-13%)
Fat stores: 6-8 lbs (20-26%)
Subtotal: 16-20 lbs

Total: 26-32 lbs (within recommended 25-35 lb range)

Why Fat Stores Are Essential

Maternal Energy Reserves:

Fuel for labor and delivery
Breastfeeding energy (500 extra calories/day needed)
Recovery from childbirth
Buffer against postpartum stress

Healthy Fat Gain: 6-8 lbs is normal and beneficial, not excessive

Calculating Your Ideal Weight Gain

Step 1: Calculate Pre-Pregnancy BMI

Formula: BMI = Weight (lbs) ÷ [Height (inches)]² × 703

Example:

Pre-pregnancy weight: 140 lbs
Height: 5’5” (65 inches)
BMI = 140 ÷ (65 × 65) × 703 = 23.3 (Normal weight)

Step 2: Determine Your Range

Based on BMI 23.3 (Normal):

Recommended total gain: 25-35 lbs
Target midpoint: 30 lbs

Step 3: Track by Trimester

First Trimester Goal: 2-4 lbs Second Trimester Goal: 12-14 lbs (1 lb/week × 14 weeks) Third Trimester Goal: 11-13 lbs (1 lb/week × 13 weeks) Total: 25-31 lbs ✓

Step 4: Monitor Weekly Progress

Starting Week 14:

Weigh yourself weekly (same day, same time, same scale)
Aim for 0.8-1 lb per week
Track trends, not daily fluctuations
Adjust diet/activity if consistently over/under

Special Considerations

Twin Pregnancies

Higher Weight Gain Required:

Pre-Pregnancy BMI	Recommended Twin Weight Gain
Underweight	50-62 lbs
Normal weight	37-54 lbs
Overweight	31-50 lbs
Obese	25-42 lbs

Weekly Rate (2nd/3rd Trimester):

Normal BMI: 1.5 lbs/week
Overweight BMI: 1.25 lbs/week
Obese BMI: 1.1 lbs/week

Why More Weight?

Two babies (14-16 lbs combined)
Larger placenta(s) (2-4 lbs)
More amniotic fluid (4 lbs)
Increased blood volume
Higher metabolic demands

Triplet Pregnancies

Recommended Weight Gain:

Normal BMI: 50-60 lbs
Overweight/Obese: 40-50 lbs
Rate: Up to 1.5-2 lbs/week in 2nd/3rd trimester

Teen Pregnancies

Growing Teens Need More:

Add 5-10 lbs to standard recommendations
Body still growing + supporting pregnancy
Higher nutritional demands
Closer monitoring essential

Age Over 35

Standard Guidelines Apply, But:

Higher risk for gestational diabetes
Increased preeclampsia risk
More monitoring recommended
Focus on nutrient-dense foods

Risks of Inadequate Weight Gain

Too Little Weight Gain

Maternal Risks:

Nutrient deficiencies (iron, calcium, folate)
Fatigue and weakness
Anemia
Delayed postpartum recovery
Insufficient milk production

Fetal Risks:

Low birth weight (<5.5 lbs)
Preterm birth
Developmental delays
Weak immune system
Increased infant mortality risk
Long-term health issues

Who’s at Risk:

Women with eating disorders
Severe morning sickness (hyperemesis gravidarum)
Food insecurity
Very active lifestyles without increased intake

Risks of Excessive Weight Gain

Too Much Weight Gain

Maternal Risks:

Gestational diabetes (4× higher risk)
Preeclampsia (high blood pressure)
Varicose veins
Sleep apnea
Back and pelvic pain
Increased C-section likelihood
Difficult postpartum weight loss
Obesity retention long-term

Fetal Risks:

Macrosomia (baby >9 lbs)
Birth complications (shoulder dystocia)
Increased C-section need
Childhood obesity risk (2-3× higher)
Future metabolic syndrome
Type 2 diabetes in adulthood

Who’s at Risk:

Sedentary lifestyle
Poor diet quality (processed foods, high sugar)
Emotional eating
Misunderstanding “eating for two”

Healthy Weight Gain Strategies

Nutrition Guidelines

Calorie Needs by Trimester:

First trimester: No extra calories needed
Second trimester: +340 calories/day
Third trimester: +450 calories/day

Important: This is modest - equivalent to:

340 calories: Greek yogurt + apple + almonds
450 calories: Peanut butter sandwich + glass of milk

Nutrient-Dense Food Choices

Prioritize These Foods:

Protein (75-100g daily):

Lean meats, poultry, fish
Eggs
Beans and lentils
Greek yogurt
Nuts and seeds

Calcium (1000mg daily):

Dairy products
Fortified plant milks
Leafy greens (kale, collards)
Almonds
Sardines with bones

Iron (27mg daily):

Red meat
Poultry (dark meat)
Beans and lentils
Fortified cereals
Spinach (with vitamin C for absorption)

Folate (600mcg daily):

Leafy greens
Citrus fruits
Fortified grains
Beans
Prenatal vitamin

Healthy Fats:

Avocados
Nuts and nut butters
Olive oil
Fatty fish (salmon, sardines)
Chia and flax seeds

Foods to Limit or Avoid

Limit:

Added sugars (<25g daily)
Saturated fats (<10% of calories)
Sodium (<2300mg daily)
Caffeine (<200mg daily)
Processed foods

Avoid:

Raw or undercooked meats/eggs
High-mercury fish (shark, swordfish, king mackerel)
Unpasteurized dairy/juices
Alcohol (completely)
Excessive vitamin A (>10,000 IU daily)

Safe Exercise During Pregnancy

Benefits:

Controls weight gain
Reduces gestational diabetes risk (40% reduction)
Improves mood and energy
Eases back pain
Promotes better sleep
Faster postpartum recovery

Recommended Activities:

Walking (30 min/day, 5 days/week)
Swimming and water aerobics
Stationary cycling
Prenatal yoga
Low-impact aerobics
Strength training (light weights)

Exercise Guidelines:

Get doctor clearance first
Moderate intensity (can talk while exercising)
Avoid overheating
Stay hydrated
Stop if pain, dizziness, or bleeding occurs
Avoid contact sports and falling risks

Monitoring Your Weight Gain

How to Weigh Yourself

Best Practices:

Same scale every time
Same time of day (morning after bathroom)
Same clothing (or naked)
Once weekly (not daily)
Track trend, not individual readings

Understanding Fluctuations

Normal Weekly Variations:

±2-3 lbs due to water retention
Higher after salty meals
Lower after bowel movements
Affected by hydration levels

Don’t Panic If:

One week shows no gain
Occasional 2-3 lb jump
Weight plateaus for 1-2 weeks
Minor fluctuations between appointments

Do Consult Doctor If:

Sudden gain of >5 lbs in one week
No weight gain for 4+ weeks (2nd/3rd trimester)
Total gain significantly below or above range
Rapid gain with swelling, headaches (preeclampsia signs)

Tracking Tools

Methods:

Pregnancy weight gain apps (Ovia, Pregnancy+)
Printable weight tracking charts
Prenatal appointment records
Weekly photo journal
Measurements (belly, arms, thighs)

Postpartum Weight Loss

What to Expect

Immediate Loss (Birth):

Baby: 7-8 lbs
Placenta: 1-2 lbs
Amniotic fluid: 2 lbs
Blood and fluids: 2-3 lbs
Total: 12-15 lbs lost immediately

First 6 Weeks:

Additional fluid loss: 5-8 lbs
Uterine shrinkage (involution)
Still retaining: 10-15 lbs above pre-pregnancy weight

6 Months Postpartum:

Breastfeeding burns 500 cal/day
Gradual loss of 1-2 lbs/month
Most women: Within 10 lbs of pre-pregnancy weight

12 Months Postpartum:

Many return to pre-pregnancy weight
Some retain 5-10 lbs (often permanent)
Breastfeeding aids weight loss

Safe Postpartum Weight Loss

Do:

Wait 6 weeks before dieting (longer if breastfeeding)
Aim for 1-2 lbs loss per week maximum
Breastfeed if possible (burns calories)
Eat nutrient-dense foods
Exercise gradually (walking → cardio → strength)
Get adequate sleep (affects weight loss hormones)

Don’t:

Crash diet (<1800 cal/day if breastfeeding)
Use weight loss pills or supplements
Over-exercise before cleared
Compare yourself to celebrities
Stress about immediate weight loss

Frequently Asked Questions

How much weight should I gain during pregnancy?

It depends on your pre-pregnancy BMI. Normal-weight women should gain 25-35 lbs, underweight women 28-40 lbs, overweight women 15-25 lbs, and obese women 11-20 lbs. Twin pregnancies require higher gains.

Is it normal not to gain weight in the first trimester?

Yes, very normal. Many women gain only 1-4 lbs in the first trimester, and some lose weight due to morning sickness. Significant weight gain typically begins in the second trimester.

Can I diet during pregnancy to avoid gaining too much weight?

No. Restricting calories or “dieting” during pregnancy can harm fetal development. Instead, focus on nutrient-dense foods, appropriate portions, and regular exercise. If gaining excessively, work with your doctor to adjust safely.

How can I avoid gaining too much pregnancy weight?

Eat nutrient-dense whole foods, control portion sizes, limit added sugars and processed foods, stay active with doctor-approved exercise (30 min daily), track your weight weekly, and increase calories modestly (340-450 cal/day in 2nd/3rd trimester, not “eating for two”).

Does morning sickness affect pregnancy weight gain?

Yes. Severe morning sickness (hyperemesis gravidarum) can cause weight loss in the first trimester. This is usually compensated in the second trimester as symptoms subside. Inform your doctor if you’re losing >5% of body weight.

How much weight do you gain per week in pregnancy?

In the first trimester, minimal gain (0.5-1 lb total per week). In the second and third trimesters: 0.8-1 lb/week for normal-weight women, 0.5-0.7 lbs/week for overweight women, and 0.4-0.6 lbs/week for obese women.

Should I eat for two during pregnancy?

No. This is a common myth. You only need an extra 340 calories in the second trimester and 450 in the third - not double your intake. Focus on nutrient quality, not quantity.

Can I lose weight during pregnancy if I’m overweight?

Weight loss is not recommended during pregnancy, even if overweight. However, obese women can gain on the lower end of recommendations (11-20 lbs) safely. Always work with your healthcare provider.

How do I calculate my pregnancy weight gain goal?

Calculate your pre-pregnancy BMI, then use IOM guidelines: Underweight (28-40 lbs), Normal (25-35 lbs), Overweight (15-25 lbs), Obese (11-20 lbs). Adjust for multiples. Track weekly starting in second trimester.

What happens if I gain too little weight during pregnancy?

Too little weight gain increases risk of low birth weight, preterm delivery, developmental issues, and infant health problems. Your doctor may recommend nutritional counseling, increased calorie intake, or dietary supplements.

Conclusion

Healthy pregnancy weight gain is essential for both maternal and fetal health. This free pregnancy weight gain calculator provides personalized recommendations based on established medical guidelines to help you track your progress safely.

Remember that every pregnancy is unique. While these ranges provide helpful targets, individual circumstances may require adjustments. Regular prenatal care ensures your weight gain supports a healthy pregnancy and sets the foundation for postpartum recovery.

Calculate your ideal pregnancy weight gain now and track your journey toward a healthy pregnancy and baby!

Medical Disclaimer: This pregnancy weight gain calculator provides general educational information based on IOM/ACOG guidelines. It does not replace personalized medical advice from your healthcare provider. Individual circumstances (medical conditions, multiples, age, etc.) may require different recommendations. Always consult your obstetrician or certified nurse-midwife for guidance specific to your pregnancy.