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Free Endurance Calculators & Race Planning Tools

Use 39 free endurance calculators to plan race pace, training zones, cycling power, swim workouts, fueling, and race day—no signup required.

Start with your goal

All Endurance Calculators

30-Minute Run Threshold Calculator

Estimate running lactate threshold pace, LTHR, and training zones from a repeatable 30-minute field test. Supports pace per km and mile.

Running

Reference Weight Formula Comparison

Compare historical Hamwi and Devine height-based reference weights with clear limits—never presented as ideal racing or weight-loss targets.

NutritionGeneral

VDOT Calculator & Race Predictor

Calculate VDOT from a recent race, predict equivalent 1500m-to-marathon times, and get transparent training paces per km and mile.

Running

VO2 Max Calculator & Fitness Estimator

Estimate VO2 max from a Cooper 12-minute test, 1.5-mile run, or maximum-to-resting heart-rate ratio.

RunningGeneral

PacePro - Race Pace Calculator

Calculate running pace per km and mile, cumulative race splits, and equivalent times for 5K, 10K, half marathon, or marathon goals.

RunningTriathlon

SWOLF Calculator

Calculate SWOLF from one length's time and arm-cycle count. See cycle rate, pool length per cycle, and 100 m or 100 yd pace for like-for-like swims.

Swimming

Cycling FTP Calculator

Calculate cycling FTP from 20-minute, Zwift ramp, or CTS 2×8-minute test power. See each multiplier, W/kg, and FTP-relative zones.

Cycling

Running Age Grade Calculator

Calculate a running age-grade percentage and age-adjusted time for ages 30–99 at 5K, 10K, half marathon, or marathon.

GeneralRunning

Cycling Power Zones (FTP)

Calculate seven contiguous cycling power zones in watts from FTP, including recovery, endurance, threshold, VO2 max, and sprint ranges.

CyclingTriathlon

CSS Swim Pace Calculator

Calculate Critical Swim Speed from 400m and 200m time trials, with training pace per 100 meters and 100 yards plus longer splits.

SwimmingTriathlon

Swim Pace Converter

Enter a 100, 200, or 400 meter or yard swim time to calculate pace per 100m and 100yd, then estimate longer pool and triathlon times.

SwimmingTriathlon

Advanced HR Zone Calculator

Calculate heart-rate training zones with Karvonen, maximum-HR, or running-specific lactate-threshold methods.

GeneralRunningCycling

Run-Walk Strategy Calculator

Calculate finish time and average pace for timed run-walk intervals.

RunningTriathlon

Track Split & Lane Calculator

Calculate 200m pace splits, full-lap targets, and same-line lane distances on a standard 400m track using official measurement lines.

Running

Hill Grade & VAM Calculator

Calculate average climb grade, vertical ascent rate, and elevation gain per distance.

RunningCycling

Race Cutoff Pace Planner

Calculate constant moving pace after stops and a safety buffer.

RunningGeneral

Cycling TSS Calculator

Estimate Training Stress Score from duration, NP, and FTP.

CyclingTriathlon

Bike Gear Speed Calculator

Calculate rollout and speed from gearing, wheel size, and cadence.

Cycling

Power-to-Weight Goal Calculator

Compare the power and weight paths to a target W/kg.

Cycling

Swim Interval & Send-Off Planner

Build repeat times, send-offs, distance, and total set time.

SwimmingTriathlon

Pool Set Distance Calculator

Total warm-up, repeats, cool-down, lengths, and swim time.

Swimming

Open-Water Sighting Cost Calculator

Estimate open-water distance and added time from a course, pace, and chosen extra percentage.

SwimmingTriathlon

Carbohydrate Loading Planner

Calculate a transparent daily carbohydrate range by body mass.

NutritionRunningTriathlon

Hydration Bottle Planner

Turn an hourly fluid target into total fluid and bottle count.

NutritionCyclingTriathlonGeneral

Race-Morning Timeline Planner

Work backward from the start time to key race-morning actions.

GeneralRunningTriathlon

Triathlon Time Budget Calculator

Check whether planned legs and transitions fit a finish-time goal.

Triathlon

Triathlon Race Day Checklist

Build, save, reorder, and share a customizable race-day gear and preparation checklist.

TriathlonGeneral

Triathlon Predictor

Calculate Sprint, Olympic, IRONMAN 70.3, or full-distance triathlon time from swim pace, bike speed, run pace, T1, and T2.

Triathlon

Marathon & Race Pace Planner

Build kilometer or mile race splits with even, positive, or negative pacing strategies.

RunningTriathlon

Endurance Fuel & Hydration Starting Points

Plan carbohydrate guidance by session duration, then calculate fluid and sodium totals from athlete-entered rates in metric or imperial units.

NutritionRunningCyclingTriathlon

Riegel Race Time Predictor

Estimate equivalent race times and paces from a recent performance with an adjustable Riegel exponent.

Running

Critical Power (CP) Calculator

Calculate your Critical Power and W' using the 3-minute all-out test, two-point, or three-point methods.

Cycling

W/kg Power Profile Analyzer

Calculate cycling watts per kilogram for 5-second, 1-minute, 5-minute, and FTP efforts.

Cycling

Race Taper Volume Calculator

Explore one illustrative exponential pre-race relative-volume curve.

GeneralTriathlon

Sweat Rate & Hydration Calculator

Estimate measured sweat rate from body-mass change, fluid intake, urine loss, and duration.

NutritionGeneral

Cycling CdA & Wattage Estimator

Roughly estimate aerodynamic drag and level-ground wattage using rider and bike mass.

CyclingTriathlon

BMR & TDEE Calculator for Athletes

Estimate BMR and activity-adjusted daily energy expenditure with published equations.

NutritionGeneral

BMI Calculator

Calculate your Body Mass Index with WHO classifications.

NutritionGeneral

Athlete Unit & Pace Converter

Convert athlete distance, weight, speed, and running pace units.

General