Why Your 10.00-Mile Run Becomes 9.99 on Strava The truth behind that tiny but frustrating difference It happens all the time—you finish a run, perfectly crafted to 10 miles with Strava Heatmaps, your Garmin watch proudly ticks over to 10.00 miles as expected, but when the activity syncs to Strava, it’s mysteriously trimmed to 9.99. There is nothing wrong with your watch or your account. This isn’t a bug. In that famous phrase, "It's a feature," an intentionally designed way that Strava handles your workout data. Strava’s Goal: Precision Your GPS device and Strava are built for different purposes. Your watch is a motivator and occasionally errs on the favourable side—it gives you quick, rounded numbers that look clean but still mathematically correct. Strava, by contrast, is the world's cycling and sports log, a semi-official global data archive for segments, challenges, and personal stats. That means Strava must treat numbers conservatively. It doesn’t round up or smooth the data—it displays the exact distance your device recorded in the raw activity file. Why A Garmin Device Might Round Up Your GPS watch isn’t being dishonest—it’s trying to be helpful Rounding for Display: If your device records 9.994 miles, it often rounds that to 10.00 for a nice, tidy number. That is mathematically correct. Strava Reads the Raw File: When your activity uploads, Strava receives the true distance (say, 9.993 or 9.999). The Result: Because the file never hits exactly 10.000 miles, Strava lists 9.99. Different brands handle distance slightly differently—some start rounding earlier, and others blend GPS with accelerometer data. Strava acts as a neutral referee, processing all brands’ data with an even hand. Why Strava Doesn’t Round Up It’s tempting to think Strava could round up—but that would create new and bigger problems. Totals Would Inflate: A hundred runs that each recorded 9.998 miles would display as 10.00, falsely adding extra miles to your yearly total. Segments Would Lose Integrity: Strava’s segment leaderboards depend on exact distances. Rounding would skew fair comparisons. To keep data consistent across millions of athletes and devices, Strava uses one universal rule: show only what’s verifiable. Strava Tax: The Take Away TL;DR: Watches can round up, Strava always rounds down. That 0.01-mile difference isn’t an error—it’s Strava’s enforcing even-handed accuracy measurements. By never 'rounding up', Strava preserves the integrity of your stats, challenges, and records. So next time you see 9.99 instead of 10.00, think of it as a slightly harsh maths teacher rather than a Strava Tax. Of course, the solution is to run just that little bit further. https://the5krunner.com/2025/10/14/strava-vs-garmin-the-climbdown-part-ii/
