Fitness Calculator

A free set of fitness calculators for 1RM (one-rep max), workout calories burned, body composition (InBody), and macros (carbs/protein/fat).

Calculate 1RM Calculate Workout Calories

TL;DR

FitCalc is a free set of fitness calculators that run right in your browser with no sign-up or install, instantly estimating your 1RM, workout calories, body composition, and macros.

Every calculation runs in your browser — your inputs are never sent to or stored on a server.

Fitness Calculators

1RM Calculator (One-Rep Max)

Estimate your one-rep max from the weight lifted and reps performed using the Epley and Brzycki formulas.

Workout Calorie Calculator

Calculate calories burned from your activity MET, body weight, and exercise duration.

Body Composition (InBody)

Enter skeletal muscle mass and body fat percentage to interpret your body composition results.

Macro / Protein Calculator

Split your target calories into carbs, protein, and fat to plan your daily macros.

Fitness Guides

How to Calculate and Use Your 1RM

What a one-rep max is, how to estimate it, and how to apply training intensity (%1RM) to your programming.

Why use FitCalc

Free & install-free — Use it straight from your browser with no sign-up or app.
No data collected — Every calculation runs in your browser; your inputs are never sent to a server.
Proven formulas — Uses widely accepted standards such as the Epley and Brzycki 1RM formulas and standard MET values.
Transparent math — Each calculator shows the formula, the method, and reference data.

Each result is an estimate for reference only. For injury prevention and accurate training prescriptions, always defer to a qualified trainer or medical professional.

Last updated: 2026-06-25