What is Calorie Calculator?
A calorie calculator combines two numbers: how much energy your body uses at rest (BMR) and how much your daily activity adds (the activity multiplier). Their product — total daily energy expenditure — is the calorie intake at which your weight stays stable. From there, subtracting a deficit produces weight loss and adding a surplus produces gain, because roughly 3,500 kcal of deficit corresponds to about one pound of fat. This calculator uses the Mifflin-St Jeor equation, the formula most dietitians consider the best general-purpose estimate, and returns maintenance plus practical loss and gain targets. Real needs vary by 10–15%, so treat the first two weeks of results as calibration.
Common Uses for Calorie Calculator
- Find your daily maintenance calories
- Set a calorie target for losing weight at a chosen rate
- Plan a surplus for building muscle
- Understand why previous diets stalled
- Adjust intake after a change in activity
BMR plus activity equals TDEE
The base number is your BMR, the energy you spend at complete rest. The activity multiplier converts it to TDEE. Getting the multiplier right matters more than the formula choice — jumping from sedentary to very active adds roughly 60% to your calorie needs.
The 500-calorie rule
A 500 kcal daily deficit is often quoted as 1 lb per week because 500 × 7 = 3,500 kcal, the approximate energy in a pound of fat. Real loss is rarely linear — water and glycogen shifts mask progress early, which is why waist measurements and weekly averages are more reliable than daily weigh-ins.
Recalibrate as you go
As you lose weight your BMR falls, and a smaller body burns fewer calories for the same activity. Recheck your numbers every 4–6 kg of loss and adjust, or the deficit quietly disappears.