Free Tools

Running Calculators

Ten free running calculators, no sign-up required. Set your paces, predict your race, plan your splits, and check the numbers before you lace up. All backed by the same science we build training plans on.

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Running Pace Calculator

Convert pace, time, and distance. Switch between min/mile and min/km, and get even splits for any race distance.

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VDOT Calculator

Enter any recent race time. Get your VDOT plus exact pace targets for easy, marathon, threshold, interval, and repetition runs.

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Race Time Predictor

Predict your finish at any distance from one recent race. Jack Daniels' VDOT math, 5K through marathon.

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Running Calorie Calculator

Calories burned running, by weight, distance, and pace. Gross and net, per mile and per km. ACSM energy-cost math.

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Heat-Adjusted Pace Calculator

Enter goal pace, temperature, and dew point. Get your heat-corrected pace and projected finish times.

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Heart Rate Zone Calculator

Karvonen heart-rate-reserve and Joe Friel LTHR methods side by side. Your five training zones, instantly.

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Marathon Pace Band Generator

Goal time in, printable per-mile pace band out. Pick even or negative splits and wear it on race day.

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Boston Qualifying Time Calculator

Age and gender in, BQ standard, gap to qualify, and the cushion you actually need to beat the cutoff.

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Treadmill Pace Converter

Match outdoor pace at any incline. ACSM energy-cost formula gives the treadmill speed for the same effort.

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Run-Walk Pace Calculator

Galloway-style run/walk ratios in, effective overall pace and finish times out, for 5K through marathon.

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The Calculators Tell You the Numbers. Pheidi Builds the Plan.

Feed your goal pace into an adaptive training plan that builds the fitness to hold it, and reshapes itself when life gets in the way. 100% free. No paywall.

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