Free Fitness Calculators for Athletes
Calculate BMI, track calories and macros, estimate body fat, find your one-rep max, determine heart rate training zones, and plan daily water intake. Free fitness tools — runs in your browser, no signup.
7 free tools — no signup required
BMI Calculator
Calculate your BMI, healthy weight range, and BMI Prime instantly
TDEE & Calorie Calculator
Calculate your TDEE, BMR, and daily calories for your goal
Body Fat Calculator
Estimate body fat % using 3 methods side-by-side — Navy, BMI-based, and skinfold
Macro Calculator
Calculate your daily protein, carbs, and fat for any diet and goal
One Rep Max Calculator
Calculate your 1RM using 6 formulas side-by-side plus a percentage training table
Heart Rate Zone Calculator
Calculate your 5 heart rate training zones using 3 methods side-by-side
Water Intake Calculator
Calculate your daily water intake based on weight, climate, and exercise
Free Fitness Calculators for Athletes — All Tools Listed
Every tool below is 100% free, requires no account, and runs entirely in your browser — your data never leaves your device.
⚖️ Free BMI Calculator
Free BMI calculator. Enter weight and height in metric or imperial to get your BMI, WHO category, BMI Prime, and healthy weight range for your height. No signup.
🔥 Free TDEE & Calorie Calculator
Free TDEE and calorie calculator. Enter your stats and activity level to get your BMR, maintenance calories, and daily calorie targets for cutting, maintaining, or bulking — with macro breakdowns. No signup.
📊 Free Body Fat Calculator
Free body fat percentage calculator. Uses 3 methods side-by-side: the US Navy formula, a BMI-based estimate, and a skinfold-based estimate — with confidence ranges for each. No signup.
🥗 Free Macro Calculator
Free macro calculator. Enter your stats and choose a goal and diet type (balanced, high-protein, keto, low-carb) to get your exact daily protein, carbs, and fat targets in grams and percentages. No signup.
🏋️ Free One Rep Max Calculator
Free one rep max calculator. Enter weight lifted and reps to get 1RM estimates from 6 formulas side-by-side (Brzycki, Epley, Lander, Lombardi, Mayhew, O'Conner) plus a full percentage training table. No signup.
❤️ Free Heart Rate Zone Calculator
Free heart rate zone calculator. Enter your age (and optionally resting heart rate) to get your 5 training zones via Karvonen, Tanaka, and 220-age methods — all side-by-side. No signup.
💧 Free Water Intake Calculator
Free water intake calculator. Get your recommended daily water intake in oz and L based on weight, climate, exercise habits, and pregnancy/breastfeeding status — with an hourly drinking schedule. No signup.