40 Free Fitness Calculators for BMI, TDEE, Body Fat & Training

BMI compares body weight with height using weight in kilograms divided by height in metres squared. It is a useful screening measure, but it does not directly measure body-fat percentage, muscle mass, fat distribution, or individual health status.

TDEE calculators estimate daily energy needs from a resting-energy equation plus an activity factor. Your real maintenance intake can differ because daily movement, training volume, body composition, food intake, and tracking accuracy vary, so use the estimate as a starting point and adjust from your weight trend.

BMR estimates the energy your body uses at rest for essential functions. TDEE starts with resting energy and adds the energy associated with normal activity and exercise, so TDEE is the more relevant estimate when planning total daily calorie intake.

Protein needs depend on body weight, training status, energy intake, and goal. The protein calculator uses goal-specific evidence-informed ranges; treat the result as a daily planning range and prioritize consistent total intake rather than chasing a single perfect number.

A calculated 1RM is an estimate based on the load and repetitions you completed. Estimates are generally more useful from lower-repetition sets performed with good technique, while higher-repetition sets introduce more variation from muscular endurance and pacing.

Zone 2 is not defined by one universal heart-rate formula. Percentage-of-max-HR and heart-rate-reserve methods use different inputs and conventions, so their ranges can differ; neither should be treated as a direct measurement of lactate threshold, ventilatory threshold, or Fatmax.

There is no single deficit that is appropriate for everyone. The calculator lets you model a moderate percentage or calorie reduction from estimated maintenance and flags very low outputs; progress, hunger, training performance, and professional guidance should inform any adjustment.

There is no universally best protein, carbohydrate, and fat percentage. Start with adequate protein, keep fat at a practical intake, and use carbohydrate for the remaining energy according to training needs and preference; the planner converts your chosen split into calorie-matched grams.

Daily fluid needs vary with body size, climate, diet, sweat rate, training duration, and other factors. The hydration calculator provides a practical baseline plus activity adjustments, but it is not a replacement for individualized guidance when fluid balance is medically important.

Use a flexible tape, keep it level, and measure consistently at the protocol locations without compressing the skin. Because a small placement change can alter the ratio, repeat measurements under similar conditions and use the same landmarks each time.

The Navy method estimates body-fat percentage from body circumferences rather than directly measuring fat tissue. Careful neck, waist, and—where required—hip measurements improve repeatability, but the result should still be treated as an estimate and is often most useful for tracking trends.

Common ideal-body-weight equations were developed for different purposes and can produce different values for the same height. Comparing several formulas as an estimate range is usually more informative than treating one calculated number as a required body weight.

No. Lean body mass is body weight minus fat mass and includes muscle, bone, organs, connective tissue, and body water. A lean-body-mass estimate therefore should not be interpreted as kilograms of skeletal muscle.

Waist-to-height ratio scales waist circumference to body height, which can make comparisons more meaningful across people of different stature. It is a screening metric for central body-size distribution, not a diagnosis or direct body-fat measurement.

A fasting schedule mainly changes when you eat; it does not guarantee a calorie deficit. Weight change still depends on overall energy intake and expenditure, so use the fasting calculator to plan meal timing rather than as a prediction of fat loss.

Wilks applies a bodyweight coefficient to a powerlifting total so lifters at different body weights can be compared within the formula’s intended categories. Formula version and reference range matter, so compare scores calculated with the same Wilks standard.

IPF GL and Wilks are different bodyweight-adjusted powerlifting formulas with different coefficients and intended use. IPF GL is the International Powerlifting Federation scoring formula, so the two scores should not be treated as interchangeable.

A common session-volume calculation is sets × repetitions × load, summed across working sets. Tonnage is useful for tracking external work, but it does not fully represent effort because range of motion, exercise choice, tempo, RPE, and proximity to failure also matter.

In resistance training, RPE 10 is commonly used to mean no repetitions left in reserve, RPE 9 about one rep left, and so on. Percentage-of-1RM charts are practical estimates rather than exact physiology, so use them with your own training history.

The tool subtracts the bar weight from your target, divides the remaining load equally between both sides, then chooses from the plate sizes you have available. If the exact target cannot be loaded, it reports the closest achievable setup instead of inventing a plate combination.

If pace stays constant, finish time is distance multiplied by pace per unit distance. The calculator handles the unit conversion and split arithmetic, but real race pace can change with terrain, weather, fatigue, stops, and pacing strategy.

Use a test that matches the protocol you can perform correctly and the population for which its equation is supported. Field-test VO2 max results are estimates; laboratory gas-exchange testing is a different measurement method and should not be treated as equivalent.

Activity calculators typically combine a MET value with body weight and duration, while wearables may also use heart rate, motion sensors, proprietary algorithms, and personal settings. Both are estimates, and individual exercise economy can make actual energy expenditure differ.

A 500 m split is the time required to cover 500 metres at the current pace. On a Concept2-style erg, small improvements in split can correspond to meaningful increases in power because the pace-to-watts relationship is nonlinear.

Watts per kilogram divides cycling power by body mass and is especially useful when gravity matters, such as climbing. It should be viewed alongside absolute watts because flat-road and time-trial performance are influenced by more than W/kg alone.

No. A fixed 1% grade is only a rule of thumb and does not reproduce every outdoor condition. This tool uses an ACSM running metabolic equation to compare speed and grade within its supported running range; it does not model wind, terrain, or individual running economy.

The classic format is 20 seconds of work followed by 10 seconds of recovery for 8 rounds, producing a 4-minute work block. The timer can help you reproduce the timing, but exercise intensity and exercise selection determine how demanding the session actually is.

At the start of each minute, you perform the programmed work; any time left before the next minute becomes recovery. Choose a workload you can complete with consistent technique so the available rest does not disappear as fatigue builds.

AMRAP is usually scored as completed rounds plus any extra repetitions before the clock expires. For meaningful comparisons, keep the workout duration, movement standards, exercise order, and rep targets the same each time.

There is no single rest-pause interval that fits every program. The correct recovery depends on the exercise, load, training goal, and method you are following, so the timer lets you set the mini-set and recovery structure instead of prescribing one universal rest period.

Start with intervals you can repeat without a major breakdown in technique or output, then adjust the work-to-rest ratio to match the exercise and training goal. Longer or harder work bouts generally require more recovery than short, simple intervals.

Karvonen uses maximum heart rate, resting heart rate, and a chosen intensity percentage. It first calculates heart-rate reserve (max HR − resting HR), applies the intensity, then adds resting HR back to create a personalized training target estimate.

Age-predicted maximum-heart-rate equations were developed from different datasets and regression models, so they are not expected to return identical values. They estimate population averages and can differ meaningfully from an individual measured maximum.

The calculator subtracts your heart rate one minute into recovery from the heart rate recorded at exercise termination. Because interpretation depends on whether recovery was active or passive and on the test protocol, compare repeated results under the same conditions.

The MAF method starts with 180 − age and then applies one method-specific adjustment based on the selected training/health category. The result is a MAF training ceiling estimate, not a measured aerobic threshold or a medical exercise prescription.

For the supported Cooper equation, distance is converted to metres and estimated VO2 max is calculated as (distance − 504.9) ÷ 44.73. The result is a field-test estimate and depends on performing a true 12-minute maximal-distance effort under suitable conditions.

For the protocol used by this calculator, step for 3 minutes on a 12-inch bench at 96 metronome clicks per minute, sit immediately, and begin a full 60-second recovery pulse count within about 5 seconds. Changing the timing changes the reference comparison.

Your final level and shuttle identify the last completed 20 m run in the selected Léger protocol. The calculator converts that point into completed shuttles, distance, final running speed, and—only where the source equation supports it—an estimated VO2 max.

Use the same push-up protocol as the selected reference table. The current ACE/CSEP-based interpretation uses a standard toes-as-pivot push-up for men and a modified bent-knee version for women, so scores from different protocols should not be compared directly.

Sit-and-reach protocols can place the foot line at different scale values, such as 23 cm, 26 cm, or zero at the toes. The calculator normalizes supported inputs to its 26 cm reference standard so you do not accidentally compare measurements from incompatible scales.