Running Pace & Heart Rate Calculator - Split Times, Race Predictor & HR Zones
Calculate target speeds, convert between min/km and mph, and calibrate your Zone 2 aerobic threshold training zones.
How to Use Pace Calculator in 3 Simple Steps
Step 1: Upload
Drag & drop your .FIT, .GPX, or .TCX activity file. All processing is 100% private in your browser.
Step 2: Process
FitCrop inspects telemetry streams, removes anomalies, recalibrates metrics, or fixes binary checksums.
Step 3: Export
Download your clean Strava, Garmin, and Zwift compatible file with 1 click. Zero server wait.
Frequently Asked Questions
How do I convert running pace (min/km) to speed (km/h)?
Divide 60 by your pace in minutes. For example, 5:00 min/km = 60 / 5 = 12.0 km/h.
What is the Karvonen formula for Zone 2 heart rate?
Target HR = ((Max HR - Resting HR) x 0.60 to 0.70) + Resting HR. It provides more accurate aerobic training zones than simple 220-age calculations.