Why don’t metrics match between Cadence and Strava (or other app or device)?

No two apps or devices will ever report identical numbers. Each one samples, filters, and smooths raw data—GPS, barometric, sensor, and timing data—using proprietary algorithms. Those algorithms are not public and vary in how they handle missing data, noise, and rounding. Even two identical devices riding side-by-side and uploading to the same service will log slightly different timestamps, satellite locks, and sample intervals, resulting in different metrics.

GPS and sensor noise

Activity data is inherently noisy. GPS accuracy degrades with speed, terrain, canopy cover, and antenna orientation. At low speeds, position “wander” increases, so small errors in latitude or longitude can exaggerate distance and elevation. Apps correct this with smoothing or filtering (Kalman filters, moving averages, or thresholding), but the level and type of filtering differ between systems.

Barometric pressure and GPS altitude are also imprecise in isolation. Devices blend both sources, often snapping altitude to digital elevation models or applying correction algorithms after upload. These differences alone can shift total ascent by tens or hundreds of meters between platforms.

The data coming in when you’re recording an activity has noise. For instance, GPS gets less accurate the slower you move and starts to jump around, and that needs to be smoothed. How much it’s smoothed is based on the algorithms no one shares.

Ascent and smoothing logic

For something like ascent: on the surface it seems like you’d think “If I increase my elevation, it should count as ascent”, but it’s not that simple. On a flat but slightly undulating road, every time GPS or the barometer thinks you increased elevation by a few inches, that would add up over time and give way too large of an ascent reading for what felt like a “flat” ride. For stats like that you have to decide what counts as “ascent”. Cadence uses a similar algorithm as Strava, which they outline at https://support.strava.com/hc/en-us/articles/115001294564-Elevation-on-Strava-FAQs.

Summary

Differences between Cadence, Strava, and other devices and apps are expected and normal. They result from:

• Slightly different sensor samples and timestamps
• Unique filtering and interpolation algorithms
• Distinct definitions of “movement,” “pause,” or “ascent”
• Post-processing corrections applied by upload services

If you suspect a specific activity has an anomaly, send the file to support@getcadence.app for review.