How maintenance calories are calculated
The Mifflin-St Jeor equation estimates resting energy needs. An activity factor estimates total daily energy use.
BMR = 10W + 6.25H − 5A + 5 (men) or − 161 (women); TDEE = BMR × activity factor; kJ = kcal × 4.184
- Convert weight to kilograms and height to centimetres.
- Use weight, height, age and sex in the BMR equation.
- Multiply BMR by the activity factor for your usual routine.
- Convert unrounded kcal to kJ by multiplying by 4.184.
Worked example: A man aged 30, weighing 80 kg and 180 cm tall, has an estimated BMR of 1,780 kcal. Moderate activity gives 1,780 × 1.55 = 2,759 kcal per day, or about 11,544 kJ.
Example daily maintenance estimates
| Formula | Age | kg | cm | Activity | Resting calories (BMR) | Maintenance calories (TDEE) |
|---|---|---|---|---|---|---|
| Male | 30 years | 80 kg | 180 cm | Moderate: Moderate exercise on 3 to 5 days a week | 1,780 kcal per day | 2,759 kcal per day |
| Female | 30 years | 60 kg | 165 cm | Light: Light exercise on 1 to 3 days a week | 1,320 kcal per day | 1,815 kcal per day |
| Male | 50 years | 90 kg | 175 cm | Sedentary: Mostly sitting, little planned exercise | 1,749 kcal per day | 2,099 kcal per day |
| Female | 45 years | 70 kg | 170 cm | Moderate: Moderate exercise on 3 to 5 days a week | 1,377 kcal per day | 2,134 kcal per day |
Swipe the table sideways to see the rest.
Adult examples only, not recommended intakes for everyone with these measurements.
Things to consider
- Differences of ±10% or more are common.
- Tracking weight over a few weeks is a better guide to maintenance needs.
- Count your usual work and exercise, not an unusually busy day.
- Pregnancy and breastfeeding change energy needs. Seek individual advice.
Frequently asked questions
What are BMR and TDEE?
BMR is the energy your body needs at rest. TDEE includes daily movement, work and exercise. This page estimates maintenance needs only. Want a target for losing weight? Use the Calorie Deficit Calculator.
What is the Mifflin-St Jeor equation?
BMR = 10 × weight in kg + 6.25 × height in cm − 5 × age in years, then add 5 for men or subtract 161 for women. It is a population estimate, not a measurement of your metabolism.
How should I choose an activity level?
Consider your usual whole week, including work and exercise. Sedentary uses 1.2, light 1.375, moderate 1.55, very active 1.725 and extra active 1.9. Exercise frequency alone does not capture every person's routine.
What is the difference between kcal and kJ?
They measure the same energy. One kilocalorie (kcal), often called a food calorie, equals 4.184 kilojoules (kJ). Conversion uses the unrounded estimate.
How accurate are calorie calculators?
Differences of ±10% or more are common. Body composition, health and activity affect actual needs. Tracking weight over a few weeks is a better guide, with professional advice where needed.
Why do the numbers change with age?
The formula subtracts 5 kcal for each year of age when other inputs stay the same. Actual age-related changes also depend on muscle mass, health and activity.
Can I use this during pregnancy or breastfeeding?
Energy needs differ during pregnancy and breastfeeding. Speak to a health professional for individual advice instead of treating this estimate as a personal intake recommendation.
Results are estimates for general information only, not financial, medical or professional advice.