Private · Browser-based · Activity file diagnostics

FIT File Repair & Recovery

Start with diagnosis, not guessing. ActivityDoctor separates safe checksum repair, deterministic anomaly repair, damaged-tail salvage and compatibility rebuild into distinct recovery paths.

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

Four repair levels

Safe Repair recalculates header and final CRC values when the declared file is otherwise intact. Smart Repair only patches conservative, locally detectable record anomalies with writable source fields. Salvage preserves every complete original message before a damaged tail. Compatibility Rebuild creates a new standardized Activity FIT from recovered Record messages.

What a rebuild may omit

A compatibility rebuild prioritizes the core workout streams that were recovered. Manufacturer-specific developer fields, some proprietary metadata, original lap/event structure and extensions may not survive the rebuilt copy. Always keep the original file.

No repair mode overwrites your selected file. Every action downloads a new copy.
Analyzing FIT file…