How is my calorie need calculated?

It first calculates your Basal Metabolic Rate (BMR) — the calories your body burns at complete rest — using the Mifflin-St Jeor equation, widely regarded as one of the most accurate BMR formulas. That BMR is then multiplied by an activity factor based on your selected exercise level to estimate your total daily calorie needs (TDEE).

Why are there two options for weight loss and gain?

A 500 kcal/day deficit or surplus is the standard "about 0.5 kg (1 lb) per week" pace, while a 250 kcal/day adjustment is a milder, more sustainable pace at roughly half that rate — useful if a more gradual change fits your goals better.

Why might my actual results differ from this estimate?

BMR formulas are population averages — individual metabolism varies based on muscle mass, genetics, hormones, and other factors not captured by age/height/weight/sex alone. Use this as a starting point and adjust based on how your actual weight trends over a few weeks.

Is my health information sent anywhere?

No. All calculations run locally in your browser with JavaScript — nothing is transmitted or stored.

CALORIE CALCULATOR

Find your daily calorie target to maintain, lose, or gain weight. Nothing leaves your browser.

Age

Sex

Height (cm)

Weight (kg)

Activity level

Calories to maintain weight2,633kcal/day

For weight loss

Mild (−0.25 kg/wk): 2,383 kcal
Standard (−0.5 kg/wk): 2,133 kcal

For weight gain

Mild (+0.25 kg/wk): 2,883 kcal
Standard (+0.5 kg/wk): 3,133 kcal

BMR calculated with the Mifflin-St Jeor equation: 1,699 kcal/day at rest, before activity.

How to use the calorie calculator

1
Choose metric or imperial units, then enter your age, sex, height, and weight.
2
Pick your activity level, from sedentary to extremely active.
3
Read your estimated daily calories to maintain your current weight.
4
Check the mild and standard calorie targets for weight loss or weight gain.

Questions

How is my calorie need calculated?: It first calculates your Basal Metabolic Rate (BMR) — the calories your body burns at complete rest — using the Mifflin-St Jeor equation, widely regarded as one of the most accurate BMR formulas. That BMR is then multiplied by an activity factor based on your selected exercise level to estimate your total daily calorie needs (TDEE).
Why are there two options for weight loss and gain?: A 500 kcal/day deficit or surplus is the standard "about 0.5 kg (1 lb) per week" pace, while a 250 kcal/day adjustment is a milder, more sustainable pace at roughly half that rate — useful if a more gradual change fits your goals better.
Why might my actual results differ from this estimate?: BMR formulas are population averages — individual metabolism varies based on muscle mass, genetics, hormones, and other factors not captured by age/height/weight/sex alone. Use this as a starting point and adjust based on how your actual weight trends over a few weeks.
Is my health information sent anywhere?: No. All calculations run locally in your browser with JavaScript — nothing is transmitted or stored.