Fitness calculations
Fitness calculations help estimate, assess, and plan to improve ones overall physical fitness.
Fitness calculators
Body fat percentage (BFP) and Lean mass percentage (LMP)
Body fat percentage (BFP) is one's total fat mass ($f$) divided by total body mass ($m$), or $BFP = f/m$. Conversely, lean mass percentage (LMP) is one's total lean mass ($l$) divided by total body mass, or $LMP = l/m$.
The most common way to estimate BFP (and, by extension, LMP) is bioelectrical impedance because it is supported by many consumer products such as bathroom scales, smart watches, and other consumer health devices. Bioelectrical impedance may have high variability from day to day but can still give a good indication of BFP on average when measured under consistent conditions (particularly time of day, time since last meal, and hydration levels).
Navy seal formula for body composition
BFP can also be estimated using the Navy Seal formula for body composition which tends to correlate strongly with bioelectrical impedance and only requires a measuring tape.
The formula differs for males and females. For males, the formula is $86.01 *log_{10} (a  n)  70.041* log_{10}(h) + 36.76$ where $a$, $n$, and $h$ represent the abdomen circumference, neck circumference, and hight, respectively, measured in centimeters. For females, the formula is $163.205 * log_{10}(w + p  n)  97.684 * log_{10}(h)  104.912$ where $w$, $p$, $n$, and $h$ represent the waist circumference, hip circumference, neck circumference, and height, respectively, measured in centimeters.
The following calculator uses the Navy seal formula for body composition to calculate BFP and LMP:
Output
Sex  male 
Abdomen circumference  35 in (88.9 cm) 
Neck circumference  16 in (40.64 cm) 
Height  72 in (182.88 cm) 
Body fat percentage (BFP)  23.12% 
Fat free mass (FFM)
Fat free mass (FFM) is simply your total body mass ($m$) multiplied by your body fat percentage, or $FFM = m * BFP$.
Output
Weight  150 lbs (68.04 kg) 
BFP  25% 
Fat mass  37.5 lbs 
Fat free mass (FFM)  112.5 lbs 
Resting Metabolic Rate (RMR)
Resting metabolic rate (RMR) is the "bare minimum" number of calories used per day to support basic life functions; in other words, it's the number of calories you would burn if you did absolutely nothing all day. RMR can be estimated by multiplying your weight in kilograms ($w$) by your body fat percentage times $100$, or $RMR = BFP *w* 100$. RMR is sometimes referred to as basal metabolic rate.
Output
Weight  185 lbs (83.91 kg) 
Resting Metabolic Rate (RMR)  1,940 Calories 
Thermic effect of food (TEF)
The thermic effect of food (TEF) is the amount of energy required to digest, absorb, and metabolize the food you eat each day. Different foods require different amounts of energy to process, with foods high in protein generally requiring the most energy. The TEF is usually around 10% to 15% of your total energy expenditure.
The TEF can be (very roughly) estimated by multiplying your resting metabolic rate by anywhere from 10% (for low protein diets) to 15% (for high protein diets).
Output
RMR  1,940 Calories 
Thermic Effect of Food (TEF)  From 194 to 291 Calories 
Nonexercise activity thermogenesis (NEAT)
Nonexercise activity thermogenesis (NEAT) is the amount of energy you use in a day for everything beyond basic life functions, except exercise. This includes activities like walking, working, and brushing your teeth. NEAT is similar to RMR, but includes activities beyond basic life functions.
NEAT can be estimated based on your typical daily activity level (not including exercise) and generally ranges from $20%$ (for bedridden individuals) to $210%$ (for people with physically strenuous occupations) of your resting metabolic rate.
NEAT Estimates
Activity level  NEAT Estimate 

Extremely low (bedridden or chairridden)  388 to 582 
Sedentary (minimal movement at work and home)  776 to 970 
Minimally active (minimal nonstrenuous movement at work and/or home)  1,164 to 1,358 
Moderately active (some strenuous movement, such as prolonged standing, at work and/or home)  1,552 to 1,746 
Very active (strenuous movement throughout most of the day, such as housework, yard work, or construction)  1,940 to 2,134 
Nonworkout energy expenditure (NEE)
Nonworkout energy expenditure (NEE) is the total amount of energy used on days you do not workout. As you might guess, it's the sum of your RMR, TEF, and NEAT, or ($NEE = RMR + TEF + NEAT$).
Output
RMR  1,500 Calories 
TEF  200 Calories 
NEAT  800 Calories 
Nonworkout energy expenditure (NEE)  2,500 calories 
Exercise related activity thermogenesis (ERAT)
Exercise related activity thermogenesis (ERAT) is the amount of energy you use in a day for exercise. ERAT is based on your body weight, the duration of exercise, and the intensity of the exercise. Exercise intensity is based on metabolic equivalent of task (MET) units, which are the ratio between a person's mass and the energy expended, thus $1 MET$ is equal to the amount of energy expanded when resting. ERAT is calculated my multiplying body mass ($w$), exercise duration in hours ($t$), and MET value, or $ERAT = w *t* MET$
MET can be estimated based on exercise intensity. Use the following table to estimate the MET for your workout:
Activity  Examples  METs 

Resting  sitting, standing, typing, eating  1  2 
Very light exercise  leisurely walk, light weight training  2  3 
Light exercise  low intensity cycling, swimming, or lifting/carrying  3  5 
Moderate exercise  climbing stairs, jogging, weight lifting  5  8 
Vigorous exercise  Highimpact aerobics, running, circuit training, heavy weight lifting  8  12 
Intense exercise  Heavy weight circuit training, highintensity cycling, sprinting  12  18 
ERAT Calculator
Output
Weight  150 lbs (68.04 kg) 
Exercise duration  60 minute (1 hours) 
MET  6 
Exercise Related Activity Thermogenesis (ERAT)  408 Calories 
Total energy demand (TED)
Total energy demand (TED) is the total number of calories you use in a day for any purpose. In other words, TED is the sum of your NEE and ERAT, or $TED = NEE + ERAT$.
Output
NEE  2,500 
ERAT  400 
Total Energy Demand (TED)  2,900 
Food macros calculator
The general wisdom to build and maintain lean mass is to eat roughly one gram of protein per pound of bodyweight or 1.6 grams of protein per pound of lean mass, depending on who you listen to. Assuming an appropriate amount of protein is being consumed:
 Eating fewer calories per day than are expended should reduce body fat faster than it reduces muscle mass
 Eating the same number of calories per day that are expended should simultaneously cause fat loss and muscle gain proportional to the intensity and duration of exercise
 Eating more calories per day than are expended should increase muscle mass faster than body fat
The "ideal" makeup of other macro nutrients in your diet are determined by a mix of genetics and personal preferences. Whether they should come primarily from carbohydrates, fats, or are roughly balanced between the two is beyond the scope of this article. However, general advice for diet is to get your nutrients from whole, minimally processed and unprocessed foods, using supplements as a "last resort" and as a safety net to get nutrients.
Output
Weight  150lbs (68.04kg) 
BFP  25% 
NEE  2,500 Calories 
TED  2,900 Calories 
Protein  150 to 180 grams per day (about 600 to 720 Calories) 
Fats and Carbs 

References
 History of the U.S. Navy Body Composition Program
 Comparison of Bioelectrical Impedance and Navy Seal Formula to Measure Body Composition in Medical Students
Broader Topics Related to Fitness Calculations
Physical Fitness
Understand and improve physical health