Making breast milk uses about 500 kcal a day in the first six months. Part of this comes from fat stored during pregnancy, so the recommended extra intake is about 330 kcal. Losing weight gradually, up to about 0.5 kg (1 lb) a week, does not usually affect milk supply.
How to use the Breastfeeding Calorie Calculator
- Age
- Weight
- Height
- Activity level
- Baby’s age
- Feeding
Results update as you type, and every field accepts the units shown in its menu.
How it works
Enter your details, activity level, your baby’s age and how you are feeding.
Inputs explained
| Field | What to enter |
|---|---|
| Age | In years |
| Weight | Units: kg, lb, st, g |
| Height | Units: cm, in, m, ft, mm |
| Activity level | Choose one: Sedentary, Lightly active, Moderately active, Very active |
| Baby’s age | Choose one: 0–6 months, 7–12 months |
| Feeding | Choose one: Exclusive breastfeeding, Partial (breast milk and formula or solids) |
What each result means
- BMR = 10×[Weight] + 6.25×[Height] – 5×[Age] – 161
- Maintenance calories before breastfeeding = [BMR]×[Activity level]
- Daily calories while breastfeeding = [Maintenance calories before breastfeeding] + [Extra for breastfeeding]
- Do not go below = 1800
Example values
How the main result changes when Age changes and everything else stays at the example values above:
| Age (years) | Daily calories while breastfeeding (kcal/day) |
|---|---|
| 15 | 2,358 |
| 22.5 | 2,307 |
| 30 | 2,255 |
| 37.5 | 2,204 |
| 45 | 2,152 |
Health note: this calculator is for education and screening only and is not a diagnosis or treatment advice. Discuss your results with a qualified clinician.
Formula
Maintenance = BMR (Mifflin–St Jeor) × activity factor
Extra for exclusive breastfeeding: +330 kcal (0–6 months), +400 kcal (7–12 months)
Partial breastfeeding: about half the extra
Worked example
Inputs — Age: 30 years; Weight: 68 kg; Height: 165 cm; Activity level: Lightly active; Baby's age: 0–6 months; Feeding: Exclusive breastfeeding.
Results — BMR = 1,400 kcal/day; Maintenance calories before breastfeeding = 1,925 kcal/day; Extra for breastfeeding = 330 kcal/day; Daily calories while breastfeeding = 2,255 kcal/day; Do not go below = 1,800 kcal/day.
Key terms
- Exclusive breastfeeding
- Only breast milk, no formula or solids.
Frequently asked questions
How many extra calories does breastfeeding need?
About 330–400 kcal a day on top of your usual needs.
Can I diet while breastfeeding?
Gradual weight loss is fine; avoid going below about 1,800 kcal a day.
Do I need to drink more?
Drink to thirst – many mothers find a glass of water at each feed helpful.