Health & fitness · 23 calculators
Health and fitness calculators
BMR, TDEE, 1-rep max, body fat, VO2 max, macros — the evidence-based formulas trainers and coaches actually use.
Start here
The 6 most-used in health & fitness
All health & fitness calculators
17 more in this category
Daily hydration calculator
Daily water intake from body weight, activity level, and climate — with electrolyte guidance for high-output athletes.
Caloric deficit calculator
Safe caloric deficit range for fat loss — weekly deficit, projected loss rate, and the minimum floor to preserve muscle.
Strength standards by bodyweight
Squat, bench, deadlift, and overhead press strength standards — novice to elite — at your bodyweight.
Resting heart rate fitness category
Classify your RHR by age and sex using AHA reference ranges — athlete, excellent, good, average, or below average.
Ideal body weight calculator
IBW from Devine, Robinson, Miller, and Hamwi formulas — and adjusted body weight for obese patients or weight-based drug dosing.
BMI calculator
Body mass index from height and weight — WHO classification, health risk, and the limitations of BMI as a standalone metric.
Daily protein target calculator
Calculate daily protein grams based on bodyweight, training goal (cut / maintain / build), and lean mass adjustments.
TDEE calculator (Mifflin-St Jeor)
Total daily energy expenditure using Mifflin-St Jeor BMR formula × activity factor, plus calorie targets for cutting / maintaining / building.
One-rep max estimator
Estimate 1RM from a sub-max set using Brzycki, Epley, and Lombardi formulas — averaged for a robust prediction.
Heart rate zones (Karvonen method)
Calculate the five training heart-rate zones using the Karvonen reserve method, which adjusts for resting heart rate.
FTP cycling power calculator
Estimate functional threshold power (FTP) from a 20-minute test using the standard 95% multiplier, plus power-zone targets.
Daily water intake calculator
Calculate daily water target based on bodyweight, training volume, and climate — with a sodium intake cross-check.
Sleep debt tracker
Calculate weekly sleep debt vs target and project the make-up time needed at extended nightly sleep.
Macro split calculator
Convert your daily calorie target into protein / carbs / fat grams using a goal-appropriate macro split.
Running pace + race time calculator
Convert pace to time and distance — predicts marathon time from a 5K PR and shows training pace targets.
VO2 max estimator (Cooper test)
Estimate VO2 max from a 12-minute Cooper test or 1.5-mile time trial — with age-graded fitness classification.
Sleep debt calculator
Quantify accumulated weekly sleep deficit vs your biological need and project the make-up time needed using evidence-based recovery models.
FAQ
health & fitness questions, answered
Q1.BMR vs TDEE — which do I use?
BMR (basal metabolic rate) is calories your body burns at total rest. TDEE (total daily energy expenditure) is BMR × activity multiplier — the actual calories you burn in a typical day. Use TDEE to set caloric targets for fat loss, maintenance, or muscle gain. BMR alone undershoots reality unless you're literally bedridden.
Q2.Which 1RM formula is most accurate?
Epley and Brzycki are the two dominant formulas; Lombardi and O'Conner are alternatives. They agree closely under 6 reps and diverge above 10. The calculator runs all four so you can see the spread. If you want one number, use Brzycki for sub-10 reps and Epley for higher rep ranges. None of them substitute for an actual heavy single — they're estimates calibrated against population data.
Q3.How accurate is the Navy method body fat?
It uses neck, waist, and (for women) hip circumferences. Validated against hydrostatic weighing with mean error of about 3-4%. More accurate than caliper readings done at home; less accurate than DEXA scans. The advantage is reproducibility — you can run it weekly with a tape measure and see trend, even if the absolute number is a few points off.
Q4.What's the right macro split?
Protein: 0.8-1.2 g/lb of bodyweight (higher end for active people in a deficit). Fat: 20-35% of total calories (don't go under 20% for hormone health). Carbs: the remainder. The calculator computes from your TDEE + goal (cut/maintain/bulk) and gives you the split in grams. Don't get fancy — protein is the lever that matters most for body composition.
Other categories