Fitness calculators that show their working
Free calculators for nutrition, body composition, strength and cardio. Each one uses a published formula and explains it in plain words.
- 5calculators
- 12published sources
- 0sign-ups or stored data
Load the bar Drag to add plates
225 lb total
2 x 45 lb per side
Estimate your bench max from any setPick a calculator
Five tools for the numbers that matter most in training and nutrition. US or metric, no sign-up.
Macro calculator
Daily calories and grams of protein, carbs and fat for your goal.
OpenBody fat percentage calculator
Body fat from a tape measure, using the US Navy method.
OpenFFMI calculator
How much muscle you carry for your height.
OpenBench max calculator
Your one rep max from any set of 1 to 12 reps, with training weights.
OpenVO2 max calculator
Aerobic fitness from resting heart rate or a timed run.
Open
Why trust the numbers
Read the methodology- Published formulasEvery calculator uses an equation from research or a professional body, and the source is listed on the page.
- Honest accuracyEach page tells you how close the estimate usually is and how to adjust from there.
- Private by designCalculations run in your browser. Nothing you type is sent or stored.
Latest guides
See all guidesVO2 max by age: charts for men and women
VO2 max charts by age for men and women, what counts as a good VO2 max in each decade, the average, and how to move up a category.
Macros for weight loss: the best split and how to set it
The best macros for weight loss: how big a calorie deficit to use, how much protein, fat and carbs to eat, and a worked example you can copy.
How to count macros: a simple step-by-step guide
What macros are and how to count them: set your targets, read a food label, weigh portions and log your day, with a worked example.
Common questions
Are StrongCalc calculators free?
Yes. Every calculator is free to use with no sign-up.
How accurate are the results?
They are estimates from published formulas. Each calculator page states the typical error of its method, which ranges from about 5% for one rep max to 3 to 4 percentage points for tape-measure body fat.
Does StrongCalc store what I enter?
No. Calculations run in your browser and the numbers you enter are never sent or saved.
Can I use metric units?
Yes. Every calculator switches between US units (lb, in) and metric units (kg, cm).
Start with your macros
It takes under a minute and needs only your age, height, weight and activity.