BMR Calculator: Find Your Basal Metabolic Rate Free
This free BMR calculator, which some people call a basal metabolic rate calculator or a resting metabolic rate calculator, puts a number on the calories burned at rest. You also see how much food energy you need on a normal day.
There is nothing to sign up for or download, and your phone does all the maths (we do not collect any data).
Use this converter to convert to the unit accepted by the calculator.
Then type the converted value into the matching box below.
+ Settings
Your BMR comes to per day.
Your calories for each lifestyle
| Your routine | What your week looks like | Number to multiply by | Your daily calorie need |
|---|---|---|---|
| Mostly sitting | Office or home work, hardly any workouts | 1.2 | |
| A bit active | 1 to 3 easy sessions, like walks or light gym days | 1.375 | |
| Fairly active | Planned workouts on 3 to 5 days | 1.55 | |
| Very active | Tough training on 6 or 7 days | 1.725 | |
| Highly active | Hard training every day, or labour work like building or farming | 1.9 |
How to use this BMR calculator
Checking your number takes five quick steps:
- Pick a unit system. The page works as a BMR calculator in kg and cm, and one tap turns it into a BMR calculator in lbs and feet.
- Fill in four details: how old you are, your sex, your height, and your weight.
- If you know your body fat %, enter it and switch to Katch-McArdle for a closer number.
- Press Calculate My BMR.
- Find the table row that matches your week to see your daily calorie target.
What is BMR (Basal Metabolic Rate)?
Picture a full day in bed, awake and not eating. Your body is still busy, and BMR is the energy it spends on that quiet work.
It pays for jobs like these:
- Pumping blood and filling your lungs
- Running your brain and nerves
- Letting your liver and kidneys filter and clean
- Holding your body heat at a steady level
- Fixing old cells and making new ones
BMR takes roughly 60 to 70% of your daily calories. Movement takes about a fifth, and breaking down meals (the thermic effect of food) takes about a tenth.
BMR vs TDEE, and Where RMR Fits In
| Term | Stands for | What it counts |
|---|---|---|
| BMR | Basal Metabolic Rate | Energy used in a strict rested state, measured after roughly 12 hours without food |
| RMR / REE | Resting Metabolic Rate / Resting Energy Expenditure | Energy used while sitting quietly with small movements. Often up to 10% above BMR |
| TDEE | Total Daily Energy Expenditure | Your BMR with your job, walking, workouts, and meals added on top |
Mifflin-St Jeor really gives RMR, but the gap is tiny. Remember this: build your meal plan on TDEE, not BMR.
How to Calculate BMR With Three Trusted Equations
Several BMR formula options exist. Our tool runs as a Mifflin-St Jeor calculator by default, since research rates it closest for most adults.
Letters used below: W is weight in kg, H is height in cm, A is age in years, and F is body fat written as a decimal (so 20% becomes 0.20).
1. Mifflin-St Jeor equation (default)
Published in 1990, it is now the first choice of most dietitians.
Women: take weight × 10, add height × 6.25, subtract age × 5, then subtract 161.
For a man aged 30, 80 kg and 178 cm: (10 × 80) + (6.25 × 178) − (5 × 30) + 5 = 1,768 calories a day.
2. Revised Harris-Benedict equation
Dating from 1919 and updated in 1984, it usually gives slightly higher answers. Select it from the settings menu, and the page turns into a Harris-Benedict calculator.
Women: BMR = (9.247 × W) + (3.098 × H) − (4.330 × A) + 447.593
3. Katch-McArdle formula
Age and sex play no part here. It looks at body composition, meaning your lean body mass, so it suits people who train a lot. Don't know your fat level yet? Check it on our body fat calculator and come back.
Work in pounds and feet? The tool converts for you.
BMR Calculator for Men and Women
One BMR calculator serves both sexes. In Mifflin-St Jeor, the only change is the last number: plus 5 for men, minus 161 for women. That creates a 166-calorie difference.
| Men | Women | |
|---|---|---|
| Usual adult range (rough) | 1,500 to 1,900 kcal/day | 1,200 to 1,500 kcal/day |
| Biggest influences | Muscle, age | Muscle, age, pregnancy, menopause |
At an equal body weight, women usually carry less muscle than men, which pulls their result down. During pregnancy, a BMR calculator for women is not enough on its own, so ask your doctor.
From BMR to Daily Calories (TDEE)
Next, multiply your BMR by the number beside your activity level. The answer is TDEE, the intake that keeps your weight where it is. A calorie calculator does the same, and our results table shows all five levels.
Example: 1,768 × 1.375 = about 2,431 calories a day.
How to Use Your BMR for Weight Loss, Maintenance or Muscle Gain
Whether you want a BMR calculator for weight loss or a BMR calculator to gain muscle, BMR is your lowest safe line, and TDEE is the dial you turn. For a sensible goal weight, our ideal weight calculator shows a healthy range for your height.
| Your aim | How much to eat | Likely speed | Using a TDEE of 2,431 |
|---|---|---|---|
| Drop weight | Calorie deficit: 300 to 500 kcal under TDEE | Roughly 0.25 to 0.5 kg each week | 1,930 to 2,130 kcal |
| Stay the same | Close to TDEE | No change | Around 2,430 kcal |
| Build muscle | Calorie surplus: 250 to 500 kcal over TDEE, plus weight training | Roughly 0.25 kg each week | 2,680 to 2,930 kcal |
Can eating below BMR harm you?
It can:
- Your system turns down its energy use to cope. Experts call this metabolic adaptation.
- Muscle gets broken down along with fat, and that pushes your BMR even lower.
- Low energy, feeling cold, constant hunger, and missing nutrients often follow.
- Losing a few kilos also lowers diabetes risk, as our prediabetes guide explains.
Tips for each goal
Small daily choices make your calorie target easier to stick to:
- Losing weight: build plates around sabzi, daal, eggs, and lean chicken, and drop sweet drinks first. Our Pakistani breakfast ideas help with low-sugar mornings.
- Gaining muscle: add a protein food to each meal and lift on at least 3 days. Men may also like our list of foods that increase testosterone, since this hormone supports muscle growth.
- For both: get 7 to 9 hours of sleep, and track your BMR again each time your weight moves by 4 to 5 kg.
What Affects Your BMR?
| Factor | How it changes BMR | In your control? |
|---|---|---|
| Muscle mass | Muscle is costly tissue to keep, so more of it lifts your resting burn | Yes |
| Age | Muscle fades over the years, and BMR slides with it | Partly |
| Sex | Men usually pack extra lean tissue, and that nudges the result up | No |
| Body size | A larger, taller frame takes more fuel to run | Partly |
| Genetics | Family traits make some metabolism run faster than others | No |
| Thyroid and hormones | A busy thyroid speeds BMR up; a sluggish one slows it | With treatment |
| Diet | Months of eating too little make the body save energy | Yes |
| Temperature | Cold, heat, or fever make the body work harder | Short term |
How to Increase BMR Naturally
A few daily habits can raise BMR and increase your metabolic rate over time:
- Gain muscle. Two to four strength sessions a week help most.
- Get your protein in. Your gut spends extra energy breaking it down, and it guards muscle during a diet.
- Skip extreme diets. Sharp cuts signal your body to save fuel.
- Rest properly. Sleeping too little leaves you hungrier the next day and may slow your body's energy use.
- Keep moving. Stairs and walks after meals lift your TDEE.
- Test your thyroid if the scale won't budge. An underactive thyroid often hides behind a low BMR.
How Accurate Is a BMR Calculator?
Any BMR calculator gives a guess. If your real burn is 1,600, Mifflin-St Jeor usually shows between 1,440 and 1,760. Lab-based indirect calorimetry is closer.
Note your weight each Friday morning for four weeks. If it stays stuck, shift your intake by 100 to 200 calories. Your BMI and body fat percentage readings add useful context to this number.
High or Low BMR: What Your Result Means
High BMR causes usually come down to a larger frame or plenty of muscle. Low BMR causes tend to be a small build, getting older, or carrying little muscle. Neither is bad, but book a check-up if your weight shifts without a reason, or you often feel drained, chilly, or shaky. Those BMR symptoms may link to the thyroid or to diabetes. Read about the early signs of diabetes to know when to test.
Frequently Asked Questions
Need a plan that fits your body?
A calculator gives you a number, but it cannot see the full picture. If your weight has been stuck for months, you feel tired most days, or digestion and thyroid issues keep getting in the way, talk to someone who can look at you as a whole person.
Medical disclaimer: Results from this BMR calculator are estimates for general learning, not medical advice. Check with a doctor before big diet changes, especially if pregnant or unwell.
