FitCalculationStart here
TDEE Calculator
Estimate the calories you burn each day from your basal metabolic rate and activity level.
Free Fitness Calculators, With the Formula Shown
FitCalculation gives you free calculators for TDEE, calorie targets, macros, protein, BMI, and body composition. Every tool shows the equation it uses and the assumptions behind the result. There is no sign-up, no ads, and your numbers never leave your browser.
Published formulas
Every calculator names the equation it uses. No hidden multipliers.
Nothing leaves your device
Calculations run in your browser. No account, no email, no tracking of your numbers.
Honest about error
These are estimates. We show the assumptions instead of pretending to exactness.
Every calculator
11 tools, grouped by what you are trying to work out.
Energy Expenditure & Calories
How many calories should I eat each day?
Work out what you burn in a day, then turn that number into a daily calorie target for losing, maintaining, or gaining weight.
Calorie Calculator
Find the calories you need to lose, maintain, or gain weight.
Calorie Deficit Calculator
Work out the daily calorie deficit and calorie target for a weekly weight-loss goal.
Calorie Surplus Calculator
Work out the daily calorie surplus and calorie target for a weekly weight-gain goal.
Bulking Calculator
Work out the calories to eat while bulking and the daily protein target to aim for.
Macros & Protein
How do I split those calories?
Turn a calorie target into daily protein, carbohydrate, and fat targets, or set a protein intake on its own.
Start here
Macro Calculator
Split your daily calories into protein, fat, and carbohydrate targets.
Protein Calculator
Calculate your daily protein intake in grams and calories from your body weight and goal.
Body Composition
What is my body actually made of?
Measure body fat and lean mass, check BMI against the standard ranges, and plan a recomposition that keeps your lean mass.
Start here
Body Fat Calculator
Estimate your body fat percentage from simple tape measurements.
Lean Body Mass Calculator
Work out your lean mass and fat mass from your body weight and body-fat percentage.
BMI Calculator
Check your body mass index and see where your weight falls on the standard range.
Body Recomposition Calculator
Estimate your maintenance calories, a modest recomposition calorie target and a daily protein target for losing fat while keeping lean mass.
How it works
Three steps, no sign-up, and the same published method on every tool.
Pick the number you need
Start from TDEE if you want maintenance calories, or jump straight to a macro, protein, or body composition target.
Enter your details
Metric or imperial, no account required. Your inputs stay in the browser and are never sent anywhere.
Read the result with its limits
Each tool shows the formula and the assumptions behind the number, so you can judge whether it is useful for you.
How these numbers are calculated
Every calculator on this site is a published equation, not a black box. Here is the method behind each group of tools.
- TDEE and BMR
Mifflin-St Jeor (1990), multiplied by an activity factor of 1.2 to 1.9
Resting burn is estimated from your age, sex, height, and weight, then scaled by how active a typical week is.
- Calorie deficit and surplus
7,700 kcal per kilogram of body fat
A target rate of weekly change is converted into a daily calorie target, and a floor is applied so the result is never an unsafe intake.
- Body fat percentage
U.S. Navy circumference method (Hodgdon-Beckett)
Estimated from height, neck, waist, and hip tape measurements. No scale required, and useful for tracking change over time.
- Macronutrients
4 kcal per gram of protein and carbohydrate, 9 kcal per gram of fat
Protein and fat are set per kilogram of body weight, and carbohydrate takes the remaining calories.
Terms these calculators use
The vocabulary behind the numbers, defined without the hand-waving.
- TDEE — Total Daily Energy Expenditure
- The total number of calories your body uses in an average day: your resting burn plus the energy spent moving, exercising, and digesting food. Eating around your TDEE is what holds your weight steady.
- BMR — Basal Metabolic Rate
- The calories your body burns at complete rest, measured while awake but totally inactive. TDEE is built on top of BMR by multiplying it by an activity factor.
- Activity multiplier
- The factor applied to your BMR to estimate TDEE, from 1.2 for sedentary up to 1.9 for very hard training or a physically demanding job. It describes your average week, not your hardest day.
- Macros — Macronutrients
- Protein, carbohydrate, and fat — the three nutrients that supply nearly all dietary energy. A macro split divides a calorie target into grams of each: 4 kcal per gram of protein and carbohydrate, 9 kcal per gram of fat.
- BMI — Body Mass Index
- A screening ratio of weight to height, calculated as weight in kilograms divided by height in metres squared, and placed against standard adult categories. BMI is a population screening measure, not a diagnosis: it cannot tell muscle from fat, so a muscular person can score high while carrying very little body fat.
- Protein
- The macronutrient that supports muscle repair and maintenance, worth 4 kcal per gram. This site sets a daily target from your body weight in kilograms — a range that rises on cutting and bulking goals, and falls back to a general range for maintenance.
Guides
A calculator gives you a number. These cover what to do with it.
How to turn your TDEE into a daily calorie target
Your TDEE is what you burn, not what you should eat. Here is how to turn that number into a target you can actually sustain.
Mifflin-St Jeor vs Harris-Benedict: which equation to use
The 1918 Harris-Benedict equation overestimates resting burn for most people. Here is what changed in 1990, and how much the difference actually matters.
How much protein do you actually need?
The useful answer is a range in grams per kilogram, not a single number. Here is where those ranges come from and how to pick one for your goal.
Why these calculators are honest about being estimates
No formula can predict your exact calorie needs, and any tool that claims to is overselling. The Mifflin-St Jeor equation is reported to land within ±10% of measured resting metabolic rate for most adults, which means a real share of people fall outside that band in both directions.
On a 2,500 kcal day, a 15% error is 375 kcal. That is the difference between a real change and no change at all, which is why this site shows the equation, states the assumptions, and tells you how far to trust the answer rather than presenting a clean number as fact.
Where a figure is a rough screening measure rather than a measurement, it says so. BMI cannot tell muscle from fat, and a tape-measure body fat estimate is not a DEXA scan.
Use the result as a starting point, then adjust it against what actually happens to your weight over two to four weeks. That feedback loop is what makes an estimate accurate in practice, and no formula can replace it.
See every formula and its sourcesRead how these tools were built