How to Analyze a GPX or FIT File Online (Free)

You finished a ride or run, you have the GPS file, and you want to actually understand the effort — where you spent time in each zone, how your splits held up, your best 5-minute power or fastest kilometre. You don't need a subscription or desktop software for that.

Stamptivity Analyze reads a GPX or FIT file and breaks the activity down in your browser: zones, splits, best efforts, and automatic segment detection. No account, nothing uploaded.

What You Can Learn From One File

Drop a file in and you get:

• Power and heart-rate zones — how long you spent in each training zone, based on your FTP or max heart rate
• Splits — per-kilometre or per-mile breakdown of pace, speed, elevation, and heart rate
• Best efforts — your peak power and fastest pace across standard durations and distances (5s, 1min, 5min, 20min; 1km, 5km, 10km)
• Segment detection — climbs and notable efforts pulled out of the track automatically
• Summary stats — distance, moving time, elevation gain, average and max speed, and more

Step by Step

1. Export your activity file

From wherever your activity lives:

• Garmin Connect — open the activity, gear icon (⚙) → Export to GPX, or grab the original FIT
• Wahoo — connect the ELEMNT via USB and copy the FIT from the activities folder
• Strava — open the activity → ⋯ → Export GPX
• COROS / Polar / Suunto / Apple Watch — export GPX from the app or companion software

Not sure how? See the per-device guides, like export GPX from Garmin or from a Wahoo.

2. Open Analyze and drop the file

Go to Stamptivity Analyze and drop your .gpx or .fit file. It parses instantly and shows the full breakdown.

3. Set your FTP and max heart rate

For meaningful power and heart-rate zones, enter your FTP (functional threshold power) and max heart rate. The zone chart recalculates immediately. If your file has no power data, the power section simply hides.

4. Read the splits, zones, and best efforts

Scroll through the splits table to see where you sped up or faded, check the time-in-zone chart for how hard the effort really was, and look at the best-efforts table for your peak intervals.

FIT vs GPX: Which Should You Analyze?

Both work. The difference is how much detail comes through:

• A FIT file straight off a Garmin or Wahoo typically includes power, cadence, temperature, and per-second samples — the richest analysis.
• A GPX file always has position and time, usually elevation, and often heart rate, but may not carry power or cadence.

If you have the FIT, use it. If all you have is GPX, that's fine — and if you need to convert between them, Convert turns a FIT into GPX, TCX, JSON, or CSV.

Everything Stays on Your Device

Analyze never uploads your file. The parsing and all the math happen locally in your browser, so your route and heart-rate data don't leave your computer. Close the tab and nothing is stored.

After Analyzing

• Recorded the same ride two ways, or want to see two attempts side by side? Use Compare to line up two files chart by chart.
• Want a shareable image of the effort? Drop the file into Stamptivity Stamp.
• Filmed it too? Overlay the data on your footage with Stamptivity Overlay.

One file holds a surprising amount of detail. Analyze pulls it out in seconds, free, and keeps it private.