Interactive Tools
Try the tools. Then see what they look like with your real data.
Calculate training targets, plan upcoming weeks, inspect activity files, or follow a live practice tool. File processing stays in your browser.
Calculate
Turn a time, pace, or running metric into a number you can use.
Pace Calculator
Free online running pace calculator — instantly calculate your target pace, estimated finish time, or distance for 5K, 10K, half marathon, and marathon. Built into Apex Run.
VDOT & Training Pace Calculator (Jack Daniels Formula)
Calculate your Jack Daniels VDOT score instantly from a recent race time or target goal. Find your exact Easy, Long Run, Marathon, Threshold, Interval & Repetition paces.
Running Efficiency & Economy Calculator
Calculate your running efficiency formulas instantly. Assess your Vertical Ratio, Duty Factor, and Aerobic Efficiency Factor (EF) from your running watch metrics.
Running Pace & Speed Converter (min/km, min/mi, km/h, mph)
Free online running pace converter — convert between min/km, min/mile, km/h, and mph. Easily convert running pace to mph for treadmill workouts and race targets.
Marathon Pace Chart & Target Splits
Free marathon pace chart with 5-minute time increments, mile and km splits, target per-km/per-mile paces, 5K/10K/half marathon checkpoints for 2:30 to 5:00 marathon finish times.
Half Marathon Pace Chart & Target Splits
Free half marathon pace chart with 5-minute increments, 5K, 10K, 15K splits, per-km and per-mile target paces for finish goals from 1:15 to 2:30.
10K Pace Chart & Target Splits
Free 10K pace chart with 2.5K, 5K, 7.5K split times, target per-km/per-mile paces, and speed in km/h for finish goals from 35:00 to 70:00.
5K Pace Chart & Target Splits
Free 5K pace chart with 1K, 2.5K, 4K split times, target per-km/per-mile paces, and speed in km/h for finish goals from 15:00 to 35:00.
Race Predictor
Apex Run's race predictor automatically forecasts your 5K, 10K, half marathon, and marathon finish times using Riegel's Formula calibrated to your last 6 weeks of real training data — no manual input required.
Heart Rate Zones Calculator
Free online running heart rate zones calculator. Instantly calculate your 5 training zones using Max HR, Karvonen (HRR), or Lactate Threshold (LTHR) methods. Switch between baseline models and fine-tune your custom zones in Apex Run.
WMA Age-Grading Calculator for Runners
Free online road running WMA age-grading calculator. Find your age-graded percentage score, prime-age equivalent finish time, and master runner level for 5K, 10K, Half Marathon, and Marathon.
Plan
Map your next race week or mileage build before you start.
Weekly Mileage Ramp-Up & 10% Rule Calculator
Build a gradual weekly mileage template using a configurable progression rate and optional recovery weeks, then adjust it around fatigue and training history.
Race Week Taper & Countdown Planner
Free interactive race week countdown and taper planner for Half Marathon, Marathon, 10K, and 5K. Generate your 7-day training schedule, race morning timeline, carb countdown, and pacing strategy.
Diagnose & Convert
Inspect, compare, or convert activity files without uploading the files for processing.
FIT, GPX, TCX, KML Converter & GPS Viewer
Keep your running records usable when switching watches. Convert FIT, GPX, TCX, KML and CSV, export GeoJSON, crop start/end points, and preview GPS tracks locally in your browser.
GPX & FIT Track Comparator — Dual Route & GPS Drift Analyzer
Run an instant track diff between two FIT, GPX, or TCX running files. Compare distance discrepancies, GPS drift, sampling interval differences, and elevation variances side-by-side with synchronized map playback.
GPS Drift & Distance Accuracy Analyzer
See where your recorded distance differs from GPS geometry. Compare FIT, GPX and TCX samples, inspect sampling gaps, and review possible drift indicators locally in your browser.
Practice
Follow a live cadence or workout timer while you train.
Running Cadence Metronome & Audio Generator (180 SPM Tool)
Find a comfortable running rhythm — practice at 120–210 spm with an online cadence metronome, or download MP3/WAV tracks for Garmin & Apple Watch.
Runner Strength & Core Timer
Stop reaching for your phone between exercises. Build a runner-focused strength routine, then follow a full-screen interval timer with upcoming-movement cues.