BMR Calculator — How Many Calories Do You Burn at Rest?

What is a BMR Calculator?

A BMR calculator (BMR कैलकुलेटर) estimates your basal metabolic rate — the calories your body burns at complete rest just to stay alive. Even lying still all day, your heart beats, your lungs breathe, your brain works, your cells repair themselves and your body keeps its temperature steady. All of that takes energy, and for most people it is the largest share of the calories they burn every day.

Knowing your BMR is the first step in any sensible diet plan. Multiply it by an activity factor and you get your TDEE (total daily energy expenditure) — the calories you need to maintain your weight. Eat less than that and you tend to lose weight; eat more and you tend to gain. This free tool calculates BMR with three respected equations and shows maintenance calories for five activity levels.

Key Features

• Mifflin-St Jeor — the equation most dietitians recommend.
• Revised Harris-Benedict for comparison.
• Katch-McArdle when you know your body fat percentage.
• Metric or imperial — cm and kg, or feet-inches and pounds.
• TDEE table for five activity levels.
• Calories per hour at rest.

How to Use It

1. Choose male or female and your units.
2. Enter your height, weight and age.
3. Optionally enter your body fat % for the Katch-McArdle result.
4. Read your BMR, then find your activity level in the table for daily calories.

The BMR Formulas

Mifflin-St Jeor (1990)

• Men: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5
• Women: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161

Example (man): 30 years, 170 cm, 70 kg → 700 + 1,062.5 − 150 + 5 = 1,618 kcal/day.
Example (woman): 30 years, 160 cm, 60 kg → 600 + 1,000 − 150 − 161 = 1,289 kcal/day.

Revised Harris-Benedict (Roza & Shizgal, 1984)

• Men: 88.362 + 13.397 × W + 4.799 × H − 5.677 × A
• Women: 447.593 + 9.247 × W + 3.098 × H − 4.330 × A

For the same man this gives about 1,672 kcal, and for the woman about 1,368 kcal — a little higher than Mifflin-St Jeor, which studies have found tends to be closer to measured values for most people today.

Katch-McArdle

BMR = 370 + 21.6 × lean body mass (kg). It uses muscle and other lean tissue instead of total weight, so it can be more accurate for very muscular or very lean people — but only if your body fat figure is reliable. A 70 kg man with 20% body fat has 56 kg of lean mass, giving about 1,580 kcal. Our Body Fat Calculator can estimate your body fat.

From BMR to Daily Calories (TDEE)

Most office workers who exercise a few times a week fit "lightly" or "moderately active". People commonly overestimate their activity — if unsure, pick the lower level and adjust after watching your weight for a few weeks. Our Calorie Calculator builds on this with targets for weight loss or gain.

Where Your Daily Calories Go

• BMR — usually the largest part of the daily total for most people.
• Thermic effect of food — around a tenth of intake, the energy used to digest and process food (protein costs the most).
• Non-exercise activity (NEAT) — walking, standing, household work, fidgeting. It varies enormously between people.
• Exercise — often a smaller share than people expect.

This is why moving more throughout the day — taking stairs, walking during phone calls — can matter as much as gym sessions.

Using BMR for Weight Goals

• Maintain: eat around your TDEE.
• Lose weight: a deficit of about 300–500 kcal a day below TDEE is a common, sustainable starting point.
• Gain muscle: a small surplus of about 200–300 kcal a day, combined with strength training and enough protein.

Weigh yourself under the same conditions once or twice a week, and adjust your intake by 100–200 kcal if your weight is not moving in the direction you want after two or three weeks. Formulas are a starting estimate; your body's response is the real measure.

Worked Example: Planning a Gentle Deficit

Take the woman from the example above: 30 years, 160 cm, 60 kg, BMR about 1,289 kcal. She works at a desk and walks or does yoga three times a week, so "lightly active" fits, giving a TDEE of about 1,772 kcal. A 400 kcal deficit means eating around 1,370 kcal a day — still above her BMR, so her body gets enough energy for its basic functions while she loses weight gradually. After three weeks she checks her weekly average weight. If it has not moved, she trims another 100–150 kcal or adds a daily walk; if she is losing faster than she would like, she eats a little more. The formula is the starting point; her real results guide the adjustments.

Metric and Imperial Units

All three equations are defined in kilograms and centimetres. If you choose feet-inches and pounds, the calculator converts exactly (1 inch = 2.54 cm, 1 lb = 0.45359237 kg) before applying the formula, so the result is the same whichever units you use. A height of 5 ft 7 in is 170.2 cm, and 154 lb is 69.9 kg.

What Affects BMR?

• Body size: larger bodies burn more energy.
• Muscle mass: muscle uses more energy at rest than fat.
• Age: BMR tends to fall gradually with age, largely through muscle loss.
• Sex: men usually have more muscle, so a higher BMR at the same weight.
• Genetics, hormones and health: thyroid conditions, for example, can raise or lower metabolic rate.
• Severe dieting: long, very large calorie deficits can reduce energy expenditure.

Can You Raise Your BMR?

Not dramatically, but you can protect and slightly increase it. Strength training two or three times a week builds and maintains muscle. Enough protein supports muscle and has the highest thermic effect. Good sleep and avoiding crash diets help keep energy expenditure from dropping. Claims that particular foods or supplements "boost metabolism" significantly are usually exaggerated.

Common Mistakes

• Eating at BMR to lose weight — BMR excludes all movement, so this is usually a large deficit.
• Overestimating activity level, which inflates TDEE.
• Treating the number as exact — individual BMR can differ by around 10%.
• Using an old weight — recalculate as your weight changes.

Who Should Be Careful

These equations are designed for healthy, non-pregnant adults. Children and teenagers, pregnant or breastfeeding women, older adults with health conditions, athletes in heavy training and anyone with a medical condition affecting weight or metabolism should get personalised advice from a doctor or registered dietitian.

Quick Glossary

• BMR: basal metabolic rate — calories burned at complete rest.
• RMR: resting metabolic rate — similar, measured under looser conditions.
• TDEE: total daily energy expenditure — BMR plus all activity.
• Lean body mass: body weight minus fat.
• kcal: kilocalorie, the "calorie" on food labels.

Why Use This BMR Calculator?

It shows three formulas side by side so you can see the range, supports both metric and imperial units, adds a ready TDEE table for every activity level and explains how to use the numbers for real goals. It is free, needs no sign-up and nothing you enter leaves your browser. Pair it with our BMI Calculator and Ideal Weight Calculator for a fuller picture of your health numbers.

BMR Calculator — Key Facts

Frequently Asked Questions

Explore More Prompt Minds Tools

BMR Calculator works great alongside our other free tools. Every Prompt Minds tool runs entirely in your browser — no sign-up, no uploads, no watermarks. Browse all free tools.