Private · Browser-based · Activity file diagnostics

FIT File Editor

Make conservative edits to a FIT activity without uploading it. V3 currently supports sport-type changes and automatically rebuilds affected checksums.

Drop your .FIT file here

Analysis runs locally in a Web Worker. Your workout file is not uploaded.

No upload No account Browser-only processing

activity.fit

Recovery confidence
Sport
Distance
Duration
Start

FIT health report

Activity stats

Average heart rate

Max heart rate

Average cadence

Average power

Private route map

Vector-only track visualization. No map tiles or GPS coordinates are requested from a third-party map service.

Recovery estimate

Repair & recovery options

Detected anomalies

Activity record sample

The interface downsamples very large activities for display. Repair logic works from the complete local file.

#TimeHRkm/hAltitudeCadencePower

Why the editor is intentionally conservative

FIT files are structured binary records. Arbitrary changes to timestamps, distances or definitions can make a file internally inconsistent. ActivityDoctor exposes edits only when it can locate and rewrite the underlying FIT field deterministically.

Need to repair bad samples?

Use Smart Repair on the Diagnosis tab for conservative timestamp, GPS, heart-rate, cadence, power and elevation anomaly handling.

Analyzing FIT file…