How to Add Cycling Power Data Overlay to Your Video

Power is the most honest metric in cycling. Speed changes with wind and gradient; heart rate lags behind effort; but watts are instantaneous and unambiguous. If you're making cycling content — a climb attempt, a threshold effort, a race — showing your live power output tells the viewer exactly how hard the effort really was.

This guide covers how to get your power data out of a FIT file and overlay it on your cycling video as a live gauge.

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What You Need

• A FIT file from a cycling computer with power meter data (Garmin, Wahoo, Hammerhead Karoo)
• A video from your ride (GoPro, action camera, or phone)
• A desktop browser

Important: Power data is stored in FIT files, not GPX. Standard GPX exports from Strava or Garmin Connect drop power. You need the original FIT file to preserve watts.

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Getting a FIT File With Power Data

From Garmin Connect

1. Open the activity on connect.garmin.com
2. Click the gear icon (⚙) → Export Original
3. This downloads the .fit file directly from your device — not the processed GPX

Do not use "Export to GPX" for power overlay work — Garmin's GPX export does not include power data.

From Wahoo

1. Connect your ELEMNT to your computer via USB
2. Browse to the activities folder on the device
3. Copy the .fit file for the relevant ride

From Hammerhead Karoo

1. Open the ride in the Karoo app
2. Export as FIT

From Strava (limited)

Strava does not expose raw FIT files via the standard export. If your device synced to Strava, you still need to export the FIT directly from the device or from Garmin/Wahoo software. Strava's GPX export strips power.

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Loading Power Data Into Stamptivity Overlay

Stamptivity Overlay accepts FIT files directly — no conversion needed.

1. Open Stamptivity Overlay
2. Load your video
3. Drop the .fit file (not GPX) into the GPS/telemetry zone
4. The tool parses the FIT and makes all recorded channels available — GPS, speed, HR, cadence, and power

Then add gauges:

• Speed — current speed
• Heart Rate — live BPM
• Cadence — pedalling cadence
• Power — live watts (add from the gauge panel)

Drag the gauges to position them. A common layout for climbing content:

• Power gauge (large, prominent) in the lower-left or lower-right
• HR and cadence as secondary gauges nearby
• Map in the opposite corner

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Tips for Power Overlay

Show 3-second or 5-second average power, not raw: Raw wattage oscillates significantly every pedal stroke and is hard to read in a video. Most overlay tools, including Stamptivity, smooth the power curve automatically — if you need to adjust, use a FIT file editing tool like FIT File Tools to apply rolling average before loading.

Power zones add context: Knowing someone is at 320W means more if you know their FTP. Consider adding a text widget with your FTP or your zone breakpoints.

Best moments to show power data:

• Climb attempts where sustained watts tell the story
• Threshold or VO2 max efforts
• Sprint finishes (peak power is the dramatic metric)
• Interval sessions where the structure is visible in the power trace

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Checking That Your FIT File Has Power

Not all FIT files contain power data — only rides recorded while connected to a power meter. If power doesn't appear as an available gauge after loading the FIT, the file doesn't contain it.

To verify before loading, use Stamptivity Convert to convert your FIT to CSV — look for a power column with non-zero values.

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After the Video: Stats Image

After creating your power overlay video, use the same FIT file in Stamptivity Stamp to create a stats image showing your normalised power, average watts, max power, and route map — a matching thumbnail for YouTube or post for social media.