Running Calculators & Tools Hub

Free running calculators for pace, race prediction, splits, heart rate zones, VO2 max, marathon fueling, hydration, age grading, and training pace planning.

Open the AI Run Planner to turn any calculator result into a week-by-week plan.

Pace & race planning

Convert finish times, predict equivalent performances, and build checkpoint splits.

Running Pace Calculator: Time, Distance & Min/Km — Free running pace calculator. Convert finish time and distance into average pace per km or mile for 5K, 10K, half marathon, and marathon.
Pace Converter — Convert running pace between min/km and min/mile.
5K Pace Calculator — Convert a 5K goal time into pace per km and mile with km splits.
5K Pace Chart — Interactive pace table for 5K finish times from 20 to 45 minutes.
parkrun Pace Calculator — Plan your weekly parkrun target pace from a 5K goal time.
Half Marathon Pace Calculator — Convert a half marathon goal time into pace and checkpoint splits.
Marathon Pace Calculator: Finish Time to Min/Km — Convert your target marathon finish time into pace per kilometer and mile, plus useful checkpoint splits for race day.
Marathon Splits Calculator — Per-kilometer marathon splits for even or negative pacing.
Race Time Predictor from a Recent Result — Predict race finish times across distances using your latest race result and fatigue profile.
Race Splits & Negative Split Calculator — Plan even or negative race splits and get checkpoint-by-checkpoint cumulative targets.
Time Goal Calculator from Target Pace — Calculate goal finish time from target pace and distance, with cumulative split checkpoints for race execution.
Training Pace Calculator: Easy, Tempo & Intervals — Free training pace calculator for runners. Get recovery, easy, long run, marathon pace, tempo, and interval pace zones from a recent race result.
Yasso 800s Calculator — Convert a marathon goal into 800m interval times and pacing.

Walk-run & beginners

Run-walk intervals and approachable pacing for first 5Ks and parkrun.

Walk-Run Calculator — Run-walk interval recommendations for 5K, 10K, and half marathon goals.
Walking Time Calculator: How Long to Walk a 5K — Estimate walking time for 5K and other distances from your walking pace.
parkrun Pace Calculator — Plan your weekly parkrun target pace from a 5K goal time.
5K Pace Chart — Interactive pace table for 5K finish times from 20 to 45 minutes.

Heart rate & fitness

Estimate training zones, VO2 max, lactate threshold, and age-graded performance.

Heart Rate Zones Calculator (Karvonen Method) — Calculate personalized running heart rate zones using the Karvonen heart rate reserve method.
Zone 2 Heart Rate Calculator for Easy Runs — Find your zone 2 heart rate range for easy aerobic training using the Karvonen heart rate reserve method.
Max Heart Rate Calculator — Estimate max heart rate from age-based formulas and compare common models.
VDOT Calculator: Training Paces & Race Equivalents — Calculate VDOT from your race result and view equivalent predicted race times across 5K, 10K, half marathon, and marathon.
VO2 Max Calculator — Estimate VO2 max from a recent race result or a 12-minute Cooper test.
Cooper Test Calculator: 12-Minute VO2 Max — Estimate VO2 max from a 12-minute Cooper test run distance and compare fitness norms.
Lactate Threshold Heart Rate Calculator — Free lactate threshold heart rate (LTHR) calculator. Find your threshold heart rate from a 30-minute time trial or max HR and build Friel-style running training zones.
Age Grade Calculator for Runners — Estimate age-graded running performance and compare your result across age groups.

Fueling & effort

Plan hydration, race fueling, and calorie burn for training and race day.

Running Hydration Calculator — Plan hourly fluid intake for training and race day from measured sweat loss and session duration.
Sweat Rate Calculator for Runners — Calculate your sweat rate in liters per hour from pre- and post-run weight to plan hydration for training and races.
Marathon Fueling Calculator — Plan marathon fueling with carbohydrate, hydration, and sodium targets based on race duration and sweat rate.
Calories Burned Running Calculator — Estimate calories burned running using weight, distance, and pace.

Steps & stride

Translate daily steps into distance and estimate stride length for pacing.

Steps to km Calculator — Convert your step count into kilometers using your average stride length.
Steps to Miles Calculator — Convert step count into miles using your average step length.
Stride Length Calculator — Calculate average stride length from a known distance and step count.