Runner Tools
Calculators for training decisions
Five free tools for race prep and training decisions — pace math, body-mass indexing, aerobic-fitness estimates, heart-rate reserve, and training pace ranges. No sign-up, and the math runs entirely in your browser.
Calculator
Pace Calculator
Solve pace, finish time, or distance for any run or race — miles or kilometers, with a 5K-to-marathon preset list.
Open the pace calculatorCalculator
BMI Calculator
Body mass index from pounds or kilograms, with CDC adult categories and the healthy weight range for your height.
Open the BMI calculatorCalculator
VO2 Max (VDOT) Calculator
Turn a recent race time into a Daniels-style VDOT estimate you can track across training blocks.
Open the VO2 max calculatorCalculator
Karvonen Heart Rate Calculator
Estimate target heart rate from age, resting heart rate, and workout intensity with the heart-rate-reserve method.
Open the heart rate calculatorCalculator
Tinman-Style Training Pace Calculator
Turn a recent race result into VDOT, easy and tempo ranges, mile and kilometer splits, and equivalent race times.
Open the training pace calculatorHow we build these
Every calculator is a thin interface over a published formula: exact unit conversions from the international system, CDC adult body-mass categories, heart-rate reserve, and the Daniels-Gilbert VDOT equations. The math is locked by automated tests, each tool page lists its sources, and nothing you type is sent anywhere — the calculations run locally in your browser.
Tools are general educational references, not individualized advice. Read our medical disclaimer before acting on any health-related number, and pair the outputs with the reporting in our training and recovery guides.