Calorie Calculator (BMR & TDEE)
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General information only, not medical advice. Talk to a doctor or registered dietitian before making health decisions.
What this calculator does
This tool estimates how many calories your body needs each day. It shows your basal metabolic rate (BMR), which is the energy used at rest, and your maintenance calories, which add your activity level. It also shows a slightly lower and a slightly higher figure, 250 kcal either side, as a gentle range for small adjustments. It is for adults aged 18 to 100.
How to use it
- Choose your sex, enter your age and choose your units.
- Enter your height and weight.
- Pick your usual activity level.
- Read your BMR and daily maintenance calories.
Formula and source
The calculator uses the Mifflin–St Jeor equation (Mifflin et al., 1990):
- Men: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5
- Women: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161
Maintenance calories = BMR × an activity factor: 1.2 (sedentary), 1.375 (light), 1.55 (moderate), 1.725 (active) or 1.9 (very active).
Example: a 30-year-old man, 180 cm and 80 kg, has a BMR of 1,780 kcal. With moderate activity (×1.55) his maintenance is about 2,759 kcal per day.
Safe use
The lower figure is never shown below 1,200 kcal (women) or 1,500 kcal (men). These numbers are general estimates and not medical advice. If you want to change your weight, make small changes gradually and speak to a doctor or dietitian first, especially if you are pregnant, have a medical condition or take medication.
Frequently asked questions
What is the difference between BMR and TDEE?
BMR is the energy your body uses at complete rest. TDEE (total daily energy expenditure) adds the calories you burn moving, working and exercising, so it is your estimated daily maintenance need.
Why does this calculator never show very low calorie numbers?
Eating far below your needs can cause fatigue, nutrient shortages and other health problems. The lower figure is never shown below 1,200 kcal for women or 1,500 kcal for men, and extra-low diets should only be followed under medical supervision.
How accurate is the result?
It is an estimate. The Mifflin–St Jeor formula is considered one of the more reliable equations, but real needs vary by muscle mass, genetics, health and daily habits.
Which activity level should I choose?
Pick the level that matches an average week, not your best week. If you are unsure, choose the lighter option, then watch your weight and energy for a few weeks and adjust.