Free Tools
Calculators for triathlon and endurance training. No signup — everything runs in your browser.
Race Time Predictor
Estimate race times for other distances from a known result (Riegel formula).
Calculate →Swim CSS Calculator
Critical Swim Speed (CSS) pace from 400 m and 200 m tests.
Calculate →FTP Calculator
Functional Threshold Power from a 20- or 8-minute max power test.
Calculate →Running Zones
5-zone training ranges from threshold pace or heart rate.
Calculate →Pace Converter
Convert between min/km, min/mile, and km/h.
Calculate →Race Split Calculator
Even km or mile race splits for a target finish time.
Calculate →Nutrition Planner
Carbohydrate and fluid plan from race duration and intensity.
Calculate →Race-Day Checklist
Race-day prep list — check items off; saved in the browser.
Calculate →TSS Calculator
Training Stress Score — load from FTP and duration.
Calculate →Brick Workouts
Ready bike + run combined sessions for triathlon.
Calculate →Volume Planner
Distribute weekly total time across swim, bike, and run.
Calculate →Race Weight
Race-day target weight and safe rate of weight loss.
Calculate →Sweat Rate
Sweat rate from pre/post-session weight and fluid intake.
Calculate →