The 8 tools our visitors reach for first.
Check your body mass index from height and weight in seconds.
Estimate body fat percentage using the U.S. Navy tape method.
Estimate your maximum lift from any working set of reps.
Find your daily calorie needs for cut, maintain, or bulk goals.
Get your daily protein target based on weight and training.
Split your calories into protein, carbs, and fats with precision.
Daily hydration target adjusted for activity and climate.
See how your lifts compare to other athletes at your bodyweight.
Track strength, body composition, and physical benchmarks.
Check your body mass index from height and weight in seconds.
Calculate Basal Metabolic Rate to find baseline resting calories.
Calculate Total Daily Energy Expenditure based on your activity.
Estimate body fat percentage using the U.S. Navy tape method.
Check central fat distribution and cardiometabolic risk from waist and height.
Measure abdominal fat distribution and health risk using waist and hip size.
Check waist measurements against common risk thresholds.
Estimate body surface area for clinical dosing and physiologic comparisons.
Classify blood pressure readings using current clinical categories.
Estimate calories burned at rest using RMR-focused formulas.
Calculate how much of your weight is pure lean tissue.
Estimate your healthy weight range using Devine, Robinson, and Hamwi formulas.
Estimate your maximum lift from any working set of reps.
Forecast your next personal record from recent training data.
See how your lifts compare to other athletes at your bodyweight.
Calculate total and weekly volume from sets, reps, and weight.
Generate custom progression targets to keep getting stronger.
Measure fat-free mass index to track real muscle progress.
Your natural muscular ceiling based on frame and height.
Estimate your annual and monthly natural muscle gain rate.
Compare your lift standards to averages in the lifting community.
Compare your biological vs. fitness age from key markers.
Score lifestyle inputs against research-backed longevity markers.
Estimate how long until visible abs at your current rate.
Dial in calories, protein, and macros for your goal.
Find your daily calorie needs for cut, maintain, or bulk goals.
Estimate maintenance calories and plan a controlled reverse diet.
Plan a controlled calorie surplus for lean muscle gain.
Plan a sustainable deficit for your weight-loss timeline.
Get your daily protein target based on weight and training.
Split your calories into protein, carbs, and fats with precision.
Daily hydration target adjusted for activity and climate.
Set a water target from bodyweight, training load, and climate.
Optimize protein timing and portion size across meals.
Optimal loading and maintenance doses based on bodyweight.
Visualize cheat meal calories in terms of exercise equivalents.
Train hard, recover smart, avoid burnout and injury.
Predict recovery time between training sessions per muscle group.
Estimate next-day soreness from intensity, volume, and novelty.
Spot early signs of overreaching before it costs you progress.
Get the right deload week based on your last training block.
Score how well your sleep supports recovery and training adaptation.
Estimate accumulated sleep debt and catch-up time.
Build a weekly training split based on your days available.
Pace, splits, and calorie burn for running and swimming.
Convert pace, distance, and time for any run or race.
Find your exercise heart-rate zones from age and resting pulse.
Estimate recovery score and VO2 max from heart rate response.
Burn rate for walking based on distance, speed, and weight.
Energy burn for every stroke style and intensity level.
Calculate splits and pace per 100m for pool and open water.
Estimate future swimming speed and times based on frequency.
Plan muscle growth, fat loss targets, and body transformations.
Plan simultaneous fat loss and muscle gain over weeks.
Estimate weeks to reach your target waist size safely.
Estimate how long it will take to hit your target body fat percentage.
Reverse-engineer your plan from a target date to today.
The signature calculators you won't find on every generic fitness site.
Forecast your next personal record from recent training data.
Your natural muscular ceiling based on frame and height.
Compare your biological vs. fitness age from key markers.
Estimate how long until visible abs at your current rate.
Fresh tools added to the lab.
Check central fat distribution and cardiometabolic risk from waist and height.
Measure abdominal fat distribution and health risk using waist and hip size.
Check waist measurements against common risk thresholds.
Estimate body surface area for clinical dosing and physiologic comparisons.
Classify blood pressure readings using current clinical categories.
Estimate calories burned at rest using RMR-focused formulas.
Score lifestyle inputs against research-backed longevity markers.
Estimate maintenance calories and plan a controlled reverse diet.
Plan a controlled calorie surplus for lean muscle gain.
Set a water target from bodyweight, training load, and climate.
Score how well your sleep supports recovery and training adaptation.
Estimate accumulated sleep debt and catch-up time.
Build a weekly training split based on your days available.
Find your exercise heart-rate zones from age and resting pulse.
Estimate recovery score and VO2 max from heart rate response.
Plan simultaneous fat loss and muscle gain over weeks.
Estimate weeks to reach your target waist size safely.
Estimate how long it will take to hit your target body fat percentage.
Reverse-engineer your plan from a target date to today.
In-depth articles paired with the calculators you already use.
The research-backed answer for cutting, lean gains, and longevity.
A smarter strength metric than BMI for muscular athletes.
Tape, calipers, BIA, DEXA — what actually works.
Loading vs. maintenance, timing, and who actually needs it.
A common journey through our tools — from baseline to goal.
Every tool on HealthFitTools — one click away.
If you're new, start with our BMI and BMR calculators to understand your baseline, then move into the Protein and Macro calculators to build a plan around your goal.
Tape and skinfold methods typically land within 3–4% of DEXA scans for most people. They're best used to track change over time rather than as an absolute number.
For weight loss start with Calorie Calculator → Macro Calculator → Calorie Deficit Calculator. For strength start with 1RM → Strength Level → PR Predictor.
Yes. Every calculator on HealthFitTools is 100% free, requires no signup, and works on mobile and desktop.
HealthFitTools is a free library of research-backed health and fitness calculators, built for people who want straight answers without a paywall. Whether you're cutting for the summer, training for a first marathon, or chasing a bigger squat, the right calculator turns guesswork into a plan you can follow.
Our fitness calculators cover the metrics that actually matter — BMI, body fat, FFMI, one-rep max, and lean body mass — so you can benchmark where you are today and track real progress over time. The nutrition calculators handle daily calories, macro splits, protein targets, hydration, and creatine dosing using the same equations dietitians use behind the scenes.
For body recomposition and weight loss tools, we go beyond the basic deficit math: we model recomposition timelines, factor in training experience, and help you set realistic goals. The strength tools compare your lifts to thousands of athletes at your bodyweight and predict your next personal record from your most recent training data.
Every calculator is free, mobile-friendly, requires no signup, and is updated whenever the underlying research changes. If you have a tool you'd like us to build next, we're listening.