FIT, GPX, TCX Converter & GPS Viewer

What is a Running Data File?

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If you track your runs using a sports watch (like Garmin, COROS, Apple Watch, Suunto) or a mobile app (like Strava, Nike Run Club, Keep), your activity is saved in a structured data format. Common formats include:

• FIT (Flexible and Interoperable Data Transfer): A binary format developed by Garmin. It is highly compact, efficient, and supports complex multi-sport configurations, heart rate variability (HRV), running power, and custom developer data fields. This is the gold standard for sports data.
• GPX (GPS Exchange Format): An open XML-based format designed primarily for GPS coordinates (latitude, longitude, elevation, and time). Widely compatible across all GPS applications.
• TCX (Training Center XML): Another Garmin XML format that bridges the gap. It supports GPS tracks, laps/splits, and sensor data (heart rate, cadence), making it great for structured training.
• KML (Keyhole Markup Language): An XML format used by Google Earth, Google Maps, and AllTrails for rendering 3D route playbacks and visual overlays.

Why Convert Running Files?

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Ecosystems are often closed or fragmented, leaving runners with files they cannot easily use. Common conversion scenarios include:

1. Platform Migration: You want to move your historical runs from a platform that only exports GPX to a Garmin device that prefers FIT, or vice versa.
2. Data Preservation: Standard sync utilities occasionally drop running power or heart rate fields. Converting to a robust format (like FIT or TCX) preserves these metrics.
3. 3D Visualization & Mapping: Exporting to KML or GeoJSON lets you view your route in Google Earth, Mapbox, QGIS, or Leaflet.
4. Data Science & Analysis: Exporting your run to CSV allows you to open your data in Excel, Python, or R to run custom analysis on your pacing, cardiac drift, or cadence.

How to Convert FIT to KML for Google Earth

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Use the FIT to KML converter above to turn a GPS activity into a route you can view in Google Earth:

1. Select or drag your .fit file into Upload & Edit.
2. Preview the route and optionally crop its start or end before sharing. Leave Strip GPS / Location coordinates unchecked: KML needs coordinates.
3. Select KML Track to download the converted .kml file.
4. Open or import the downloaded KML file in Google Earth to view your route.

Your FIT file must contain GPS trackpoints. An indoor treadmill activity without GPS coordinates cannot produce a KML route; conversion does not reconstruct missing locations.

KML is a mapping format, not a complete replacement for the original FIT activity. Do not expect all heart rate, cadence, power, lap, or FIT developer fields to survive the conversion. Keep the original FIT file for detailed workout analysis.

Conversion runs locally in your browser without uploading your activity file for processing. The optional map preview requests tiles from external map providers, and opening the exported KML in another application is separate from the conversion.

Respecting Your Privacy: The Privacy Shield

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Sharing running tracks online is fun, but it has a massive security risk: revealing your home or work address.

Most running apps start tracking the second you walk out your door. This means the start and end points of your GPX or FIT files pinpoint your exact address.

Our Privacy Shield tool addresses this with three critical options:

• Crop Start & End: Hide the beginning or end of your route by choosing how many meters to trim. Distance and duration are recalculated from the retained points; opaque FIT metadata is also removed because it can contain locations outside the crop.
• Strip Coordinates: Share sensor measurements without the route by removing GPS coordinates and opaque FIT fields. Choose FIT, TCX or CSV for a GPS-free export; GPX, KML and GeoJSON need coordinates.
• Strip Laps & Recalculate Distance from GPS: Compare your watch’s recorded distance with a GPS-derived distance by removing firmware lap markers and recalculating from the recorded coordinates. GPS noise can still affect the result; this does not reconstruct missing sections or guarantee the official race distance.

Your workout files are parsed, edited and converted locally in your browser, using a background worker from the open-source Runner Tools project. Files are not uploaded for processing. The optional map preview requests map tiles from OpenStreetMap or Esri, so those providers can see requests for the displayed map area.

Frequently Asked Questions

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How do I merge two split FIT or GPX files into one?

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Drag and drop both .fit or .gpx files into the converter tool above, check “Merge uploaded files chronologically”, and select an export format, such as FIT File. The tool sorts the trackpoints by timestamp and exports the combined activity.

Is my running location data private during conversion?

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Your workout file stays in your browser during processing. The map preview downloads tiles for the displayed area from external map providers; this is separate from file conversion.

Will all FIT developer fields survive a conversion?

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Keep an unedited FIT-to-FIT conversion when you need the original native and developer fields. Merging preserves record-level developer measurements, but rebuilds activity metadata. Cropping or removing GPS also removes opaque developer data because it may contain locations; a notice appears before export. Other formats only retain the measurements they support.

Why does an undated route need a start time for FIT export?

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Choose an activity start time when a route, such as a KML file, has no recorded start. This identifies the FIT activity without inventing timestamps for individual points. It does not turn a route into a measured workout with an estimated pace or duration.

What is the difference between FIT and GPX formats?

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FIT is a compact binary format that stores detailed sensor data (heart rate, cadence, running power, HRV). GPX is an open XML format designed specifically for location coordinates and timestamps, supported by virtually every map and GPS platform.

Looking for More Deep Data Analytics?

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While online tools are convenient for quick conversions and privacy edits, a local-first mobile dashboard is the best way to track your long-term fitness.

The Apex Run mobile app offers:

• Shadow Runner: Automatically match and compare your runs on the exact same routes to track your pace improvements over time.
• Route Playbacks: Relive your best runs with step-by-step 2D/3D map playback.
• Local-First Database: Reads Apple Health data on your device without requiring an Apex Run account.
• Advanced Metrics: GAP (Grade Adjusted Pace), running efficiency, custom pace zones, and widgets.

Download Apex Run on the App Store to take full control of your running data today.