How your calories are calculated
This tool uses the Mifflin-St Jeor equation, the formula most dietitians consider the most accurate for estimating calorie needs. First it finds your BMR — the calories your body burns at complete rest — then multiplies it by an activity factor to get your TDEE (Total Daily Energy Expenditure), the calories you burn in a normal day.
Men: BMR = 10·kg + 6.25·cm − 5·age + 5
Women: BMR = 10·kg + 6.25·cm − 5·age − 161
Losing or gaining weight
Roughly 7,700 calories equals one kilogram of body fat. Eating about 500 fewer calories a day than your TDEE loses about 0.5 kg per week; 250 fewer loses about 0.25 kg. Gaining works the same way in reverse. Very aggressive deficits are hard to sustain and can cost muscle — slow and steady wins.
What are macros?
Your calories come from three macronutrients: protein, carbohydrates (4 calories per gram each) and fat (9 calories per gram). The split above (30/40/30) is a balanced starting point — active people and those building muscle often raise protein. Adjust to what keeps you full and consistent.
Choosing your activity level honestly
The activity multiplier has a big effect, and it's the easiest place to fool yourself. It already includes daily movement, so a desk job with a couple of gym sessions is usually Light or Moderate, not Active. When in doubt, pick the lower level — if the scale doesn't move after two or three weeks, nudge it up. Your TDEE is an estimate to test against reality, not a fixed truth.
Frequently asked questions
Why is my TDEE different from other calculators?
Most differences come down to the formula and the activity multiplier. This tool uses Mifflin-St Jeor, which research finds the most accurate for the general population, and standard activity factors. A number 100–200 calories apart from another site is normal — treat any estimate as a starting point.
How much protein should I eat?
A common guideline for active people is roughly 1.6–2.2 grams of protein per kilogram of body weight, especially when losing weight or building muscle, since protein protects muscle and keeps you full. The 30% shown above is a solid default; raise it and lower carbs if you train hard.
Should I eat back the calories I burn exercising?
Not usually — your chosen activity level already accounts for exercise, so adding it again double-counts. Only adjust if a single day is far outside your normal routine.
Why did my weight loss stall?
As you lose weight your body needs fewer calories, so a deficit that worked at the start eventually becomes maintenance. Recalculate your TDEE with your new weight every few kilograms and adjust. Day-to-day swings from water and food are also normal — judge progress over two to three weeks, not one morning on the scale.
Tools that pair with this one
- BMI Calculator — check where your current weight sits and find the healthy weight range you're steering these calories toward.
These are estimates for general information, not medical or dietary advice. Individual needs vary — consult a doctor or dietitian before making big changes, especially if you have a health condition. Formula (Mifflin-St Jeor, 1990) reviewed July 2026.