Science-Based Health & Fitness Calculators

Multi-formula comparison tools for body composition, nutrition, and training performance. Every calculator backed by peer-reviewed research.

Calculator Categories

Body Composition

BMI, body fat percentage, ideal weight, waist ratios, and body surface area calculators using validated measurement methods.

13 tools available

Nutrition & Energy

TDEE, BMR, calorie, macronutrient, protein intake, and energy balance calculators based on peer-reviewed metabolic formulas.

14 tools available

Training & Performance

One-rep max, running pace, heart rate zone, workout volume, and performance calculators grounded in exercise science.

17 tools available

Featured Tools

BMI Calculator

Calculate your Body Mass Index with WHO category classification, BMI Prime ratio, and personalised healthy weight range. Free science-based tool.

Body Fat Calculator

Estimate body fat percentage using Navy tape, Jackson-Pollock skinfold, and BMI-derived methods. Compare results from up to four validated formulas.

TDEE Calculator

Calculate your Total Daily Energy Expenditure with Mifflin-St Jeor, Harris-Benedict, and Katch-McArdle formulas. Free side-by-side comparison.

Macro Calculator — Personalised Splits

Calculate personalised protein, carbohydrate, and fat targets with four diet presets. Goal-adjusted macros based on your TDEE estimate.

One Rep Max Calculator — Epley, Brzycki & Lander

Estimate your one-rep max using Epley, Brzycki, and Lander formulas. Includes percentage table for programming sets at 50-100% of 1RM.

Workout Volume Calculator

Calculate weekly training volume per muscle group with MEV, MAV, and MRV landmark assessment. Free tool based on exercise science research.

Built by an Athlete-Technologist

PeakCalcs is built by Dan Dadovic, a PhD candidate in IT Sciences and former competitive athlete who represented Croatia in international whitewater sport. Every calculator implements a formula drawn from peer-reviewed research — AJCN, ACSM, and IOM publications — verified against known-value tests before going live.