Calorie Calculator (TDEE & BMR)
Estimate your daily calorie needs, BMR and TDEE, and the calories to eat to lose, maintain or gain weight
Last updated: October 28, 2026
Mifflin-St Jeor equation (BMR)
Your basal metabolic rate (BMR) is the energy your body uses at rest. This calculator uses the Mifflin-St Jeor equation:
Men: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5
Women: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161
TDEE (maintenance calories)
Your total daily energy expenditure (TDEE) adds the calories you burn through activity:
TDEE = BMR × Activity factor
| Activity level | Factor | |---|---| | Sedentary | 1.2 | | Light exercise | 1.375 | | Moderate exercise | 1.55 | | Hard exercise | 1.725 | | Very active | 1.9 |
Worked example
A 30-year-old man, 70 kg, 170 cm, moderately active:
- BMR = 10 × 70 + 6.25 × 170 − 5 × 30 + 5 = 700 + 1,062.5 − 150 + 5 = 1,617.5 kcal
- TDEE = 1,617.5 × 1.55 = 2,507 kcal per day to maintain weight
Calories for a goal
Eating about 500 kcal below TDEE a day leads to roughly 0.45 kg (1 lb) of weight loss a week, because one kilogram of body weight is about 7,700 kcal. Real results vary with water balance, muscle and how your metabolism adapts.
How to use the calorie calculator
- Pick your units. Switch between metric and imperial. Numbers you have already typed are converted for you.
- Enter your details. Choose your sex, and enter your age, weight and height.
- Choose an activity level. Be honest and lean towards the lower option if you are unsure. Most people overestimate how active they are.
- Pick a goal. Select maintain, lose or gain. Gentle changes of 250 to 500 kcal a day are easier to keep up.
- Read the results. You will see your BMR, your maintenance calories (TDEE), and the daily calories for your goal.
This is an estimate, not medical advice. Check how your weight changes over two to three weeks and adjust by 100 to 200 kcal as needed. Speak to a doctor or dietitian before making big changes to your diet.
Frequently Asked Questions
How many calories should I eat a day?
It depends on your age, sex, size and activity. Enter your details above to get an estimate of your maintenance calories (TDEE). Eating about that amount keeps your weight steady, and eating less or more moves it down or up.
What is the difference between BMR and TDEE?
BMR is the energy your body uses at complete rest to keep you alive. TDEE is your total daily burn: BMR plus the calories used for movement, exercise and digesting food. TDEE is the number to use when planning how much to eat.
Which formula does this calculator use?
The Mifflin-St Jeor equation, which research has found to be among the more accurate predictors of resting energy needs for most adults. Other equations, such as Harris-Benedict, give somewhat different numbers.
How many calories do I need to lose weight?
Eat below your TDEE. A deficit of about 500 kcal a day is commonly used and leads to roughly 0.45 kg (1 lb) of weight loss a week, though the real rate varies. Avoid going below about 1,200 kcal (women) or 1,500 kcal (men) a day without medical supervision.
Is a pound of fat really 3,500 calories?
It is a widely used rule of thumb, not an exact law. Weight change depends on water, muscle and how your body adapts when you eat less, so progress is rarely perfectly linear. Treat the weekly estimate as a rough guide.
How accurate is a calorie calculator?
It is an estimate that can be off by a few hundred calories either way, because two people with the same stats can burn different amounts. Use it as a starting point, then adjust based on how your weight and energy respond over a few weeks.
Should I change my calories if I exercise more?
Choose a higher activity level if your routine has really changed, and the calculator will raise your maintenance calories. Avoid double counting by not adding exercise calories on top of an activity multiplier.
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