Calculate your Basal Metabolic Rate (BMR) and discover the exact calories your body needs daily, powered by 3 scientifically-proven formulas.
| Activity Level | Calories |
|---|
A BMR calculator is a tool that estimates your Basal Metabolic Rate, which is the number of calories your body burns each day just to stay alive while completely at rest. This includes the energy your body uses to keep your heart beating, your lungs breathing, your brain functioning, and your cells repairing themselves.
Think of BMR as the fuel your body needs even if you spent the entire day lying in bed without moving a muscle. For most people, this resting energy use makes up around 70% of total daily calories burned, making it the single biggest piece of your overall energy needs.
This basal metabolic rate calculator takes your age, gender, height, and weight, and runs them through a scientifically validated formula to give you a personalised number within seconds. From there, it also shows your TDEE calculator results, meaning your total daily calorie needs once activity level is factored in.
Whether you are trying to lose weight, build muscle, or simply understand your metabolism calculator results, knowing your BMR gives you a solid starting point for setting realistic calorie targets.
This tool runs your numbers through one of three trusted equations. By default, it uses the Mifflin-St Jeor Equation, widely regarded as the most reliable BMR formula for the general population.
Here, W stands for weight in kilograms, H stands for height in centimetres, and A stands for age in years. You can switch to the Harris-Benedict or Katch-McArdle formula from the advanced settings if you prefer, with Katch-McArdle being a strong choice for lean or athletic users who already know their body fat percentage.
Once your BMR is calculated, the tool multiplies it by an activity factor to give your TDEE, which tells you how many calories you actually need depending on how active your lifestyle is.
Getting your result takes less than a minute. Just follow these steps:
There is no signup required and no data is saved anywhere, so feel free to recalculate as often as you like as your weight or activity level changes.
Once you calculate your BMR, the tool also shows your daily calorie needs calculator breakdown across six activity levels. This is where TDEE comes in, since your real-world calorie needs are always higher than your BMR alone.
| Activity Level | What It Means |
|---|---|
| Sedentary | Little or no regular exercise |
| Lightly Active | Exercise 1 to 3 times per week |
| Moderately Active | Exercise 4 to 5 times per week |
| Very Active | Daily exercise or intense training 3 to 4 times weekly |
| Extra Active | Intense exercise 6 to 7 times per week |
| Athlete Level | Very intense daily training or a physically demanding job |
Below the table, the calculator also gives you three quick calorie targets for weight loss, maintenance, and weight gain, calculated automatically from your TDEE so you don't need to do any extra maths.
There are plenty of BMR calculators online, but SolveFlow was built to be faster, cleaner, and more complete in one single screen. Here is what makes this tool worth bookmarking.
Switch between Mifflin-St Jeor, Harris-Benedict, and Katch-McArdle depending on your body type and goals.
Your BMR and full TDEE breakdown appear in under a second, with no waiting and no ads blocking the result.
This BMR calculator kg and lbs toggle lets you switch units instantly without losing your entered data.
Get automatic targets for losing, maintaining, or gaining weight without needing a separate calculator.
Fully responsive, so it looks clean and works smoothly on phones, tablets, and desktop browsers alike.
Every calculation runs in your browser. Your age, weight, and health details are never saved or shared.
This tool is useful for almost anyone curious about their metabolism, but it tends to help certain groups the most.
People trying to lose weight can use it to find a safe calorie deficit instead of guessing. People trying to build muscle can use the weight gain target to eat enough without overdoing it. Athletes and gym-goers can switch to the Katch-McArdle formula for a more precise number if they know their body fat percentage.
It also works well for nutrition students, coaches, and anyone managing a client's diet plan, since the results update instantly and can be recalculated as weight or activity changes over time.
BMR is the energy your body burns at complete rest, while TDEE adds your daily activity, exercise, and digestion on top of that number. TDEE is the figure you should actually use when planning how much to eat.
Calculate your TDEE first, then aim to eat around 300 to 500 calories below that number each day. Eating below your BMR itself is not recommended, since it can slow your metabolism over time.
Yes, the unit toggle lets you mix systems comfortably. Choose Imperial if you want to enter height in feet and inches while still typing weight separately, or stick with Metric for kg and cm throughout.
Yes, age is one of the core variables in every formula here. BMR naturally drops by roughly 1 to 2 percent each decade after turning 20, and the calculator adjusts automatically based on the age you enter.
There is no single "good" BMR, since it depends entirely on your height, weight, age, and gender. A taller or more muscular person will naturally have a higher BMR than a smaller person, and that is completely normal.
Formula-based calculators are typically accurate within 5 to 10 percent for most people, which is reliable enough for everyday planning. For lab-grade precision, a specialist can measure your BMR using indirect calorimetry.
These formulas are designed and validated for adults. Children and teenagers have very different growth-related energy needs, so a paediatrician or registered dietitian should be consulted instead of relying on an adult BMR formula.