Calc Garden

Plot No. 14 · Health & Fitness

BMR and Calorie Calculator

Estimate the calories your body burns each day. This tool uses the Mifflin-St Jeor equation to find your basal metabolic rate, then applies an activity multiplier to show your daily maintenance calories for losing, keeping or gaining weight.

Inputs
Sex
Results
Maintenance calories2,740 kcal
Basal metabolic rate (BMR)1,768 kcal
To lose weight (about 500 kcal deficit)2,240 kcal
To gain weight (about 500 kcal surplus)3,240 kcal

BMR uses the Mifflin-St Jeor equation. Maintenance calories are your BMR multiplied by an activity factor. These are estimates, not medical advice.

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How BMR and maintenance calories are estimated

Your basal metabolic rate is the energy your body uses at complete rest just to keep you alive. This calculator estimates it with the Mifflin-St Jeor equation, widely regarded as one of the most accurate. For men it is ten times weight in kilograms plus 6.25 times height in centimetres minus five times age in years, plus five. For women the final term is minus 161 instead.

Maintenance calories are higher than BMR because they account for daily movement and exercise. The tool multiplies your BMR by an activity factor, from 1.2 for a sedentary lifestyle up to 1.9 for very hard training, then shows targets for losing or gaining weight around that maintenance level.

How to use the BMR and calorie calculator

  1. Select your sex, then enter your weight, height and age.
  2. Choose the activity level that best matches your typical week.
  3. Read your maintenance calories and BMR, plus the suggested intake to lose or gain weight.

Worked examples

A moderately active man

Inputs: Male, 80 kg, 178 cm, 30 years old, moderately active at 1.55.

Result: A BMR of about 1,768 kcal and maintenance calories of roughly 2,740 kcal a day, with about 2,240 kcal suggested for a 500 kcal deficit to lose weight.

Switching to sedentary

Inputs: The same person but with a sedentary activity level of 1.2.

Result: Maintenance falls to about 2,122 kcal, showing how much activity level drives the daily target.

Limitations and common mistakes

Edge cases and limitations

  • These are estimates for the average person of your stats and are not medical or dietary advice.
  • Inputs use metric units only, so convert pounds and feet first. Body composition, medical conditions and medication can all shift your real needs.
  • The deficit and surplus shown are a flat 500 kcal, a common starting point rather than a personalised plan.

Common mistakes

  • Overstating your activity level, which inflates maintenance calories and stalls weight loss.
  • Eating below your BMR for long periods, which the tool flags as unsustainable and best avoided without professional guidance.

Frequently asked questions

What is the Mifflin-St Jeor formula?

For men, BMR equals 10 times weight in kilograms, plus 6.25 times height in centimetres, minus 5 times age in years, plus 5. For women the final number is minus 161 instead of plus 5. It is widely regarded as one of the most accurate BMR equations.

What is the difference between BMR and maintenance calories?

BMR is the energy your body uses at complete rest just to stay alive. Maintenance calories are higher because they include movement and exercise, found by multiplying BMR by an activity factor from 1.2 for sedentary to 1.9 for very active.

How many calories should I eat to lose weight?

A deficit of about 500 calories a day below maintenance leads to roughly half a kilogram of fat loss per week for many people. Do not drop below your BMR for long without professional guidance, as it can be unsustainable and unsafe.

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