Explaining the “Strava Tax”
多種運動
Why 10.00 miles on your device became 9.99 miles on Strava
Taxes! No one likes to pay them. But we can’t escape them.
We aren’t talking about the kind with W-2s – though our U.S. athletes went through that recently. We mean the kind where your 10.00-mile run magically becomes 9.99 when you upload it to Strava. It’s a phenomenon we lovingly call the Strava Tax.
We know it can be really frustrating, so we wanted to share why it happens, where it came from, and why changing it is tougher than it sounds.
💰 What is the Strava Tax?
You’ve probably been there: you finish your run or ride, see a nice round number on your device – say 10.00 – miles, upload to Strava and boom: your activity shows 9.99. That’s the “Strava Tax”. Cue endless memes, comments, circles in the parking lot, and support tickets.
This happens because Strava rounds down distances when displaying them. But why?
📒 Strava is the record of the world’s activities.
Strava’s role in the fitness ecosystem is bigger than just showing you a nice round number on your phone.
Strava is the ledger of record for human activities – a responsibility we take seriously. We’re the place where the effort gets documented, the work gets acknowledged, and the numbers carry weight, whether it’s for your own personal progress, a weekly challenge, or a world-record attempt.
Because of that, we have to record each activity as accurately and authentically as possible. We just show what was recorded, down to the second decimal point.
But how is that different than what your device shows?
📡 Devices round up. Strava doesn’t.
Your watch or head unit might say 10.00 miles. But what it actually recorded and sent to Strava might be 9.993. That means when we round it down for display, you’ll see 9.99.
Some devices—and the apps that come with them—do something different. They often "improve" the raw data to smooth it out, make it cleaner, or just make it nicer to look at.
Some considerations:
On some wearable devices, as soon as you go from 990 meters to 991 meters (0.991 km) the device shows 1.00 km.
Some devices adjust the mile split slightly—using 1609 meters instead of the precise 1609.344. (One even uses 1609.08!)
Different devices from the same brand may display the same distance differently.
These alterations vary between devices and manufacturers, and Strava sits in the middle of all of this. We’re the hub that connects Garmin to Apple to COROS to Suunto to your community—and we must be fair and neutral in how we treat that data.
That’s why we don’t adjust the raw distance we receive. We don’t add a buffer. We don’t try to reverse-engineer your tracker’s optimism or correct them on a device-by-device basis. We display the exact number that came in, rounded down, to reflect the most authentic, reliable version of the truth.
🔬 How it works
The majority of activities come to Strava as a FIT file, which includes:
A list of distances in meters at different points in time – e.g. 3.0 meters at 1 second, 6.0 meters at 2 seconds, all the way to something like 5000.0 meters at the last time recorded in the file
A “session” value at the end, which should correspond to the last distance value (e.g. 5000.0 m), which summarizes the whole activity
A lot of nuance depending on the brand. Each manufacturer has their own parser to handle any nuances in how they have chosen to write data on the device and where it is displayed later (Garmin Connect, Apple Health, etc.) for analysis.
Strava, meanwhile, has a single parsing system, which lets us turn the data into an activity and other Strava proprietary features – Segments, Best Efforts, grouped activities, etc. – and has to somehow show the same output from each FIT file no matter where it came from and what intricacies it carries. To display them consistently, Strava’s parsing system takes the following approach:
Assume the first distance point is 0.0 (though this is not always the case in every device’s distance stream)
Calculate the difference between the last point in the stream and 0.0 (for more information on how distance is calculated, check out this article)
Use the final distance in meters, regardless of whether your preferred units are imperial or metric, and
Store it exactly as provided.
For non-FIT devices (e.g. those using GPX), Strava ignores the device provided distance, which is often inconsistent, and recalculates the distance from GPS.
We then format it for display – cutting it to two decimal places, and rounding down. (If you’re keeping track, we only started using two decimal places in 2016.)
So if your device recorded 9.993 or 9.999 miles, you’ll see 9.99 on Strava. Even though your watch may have showed 10.00, the raw data might not have crossed the line.
That’s just for distance! Things get even more complicated with moving time, which has its own set of discrepancies, but we’ll need to save that for another article.
🤔 Why does Strava round down?
When Strava started in the early 2010s, GPS wasn’t as good as today. It often overestimated distance, especially on straight roads with slight GPS drift. To stay honest to the effort, we made a call starting in 2012: always round down.
We adopted the same principle we apply to racing: if you’re running a 5K and your watch says 5.00km before the finish line, you don’t stop running – you finish.
So we applied that logic to how distances were displayed. It’s a conservative approach, but one that matches the seriousness with which we view the data athletes trust us to handle.
In 2025, GPS has become more accurate but the way distance is calculated on devices is more complicated. Many devices, including from Garmin, create a “fused” distance that combines inputs from GPS, pedometers and accelerometers. (That’s how we sometimes get distance on activities that are missing GPS.) Tracks and “urban canyons” of cities often cause GPS data to overestimate distance. Considering these complexities, to remain as accurate as possible, Strava is still taking the same approach and rounding down.
This rounding policy applies to activity distance, the total distance of multiple activities, laps within an activity, segments, Routes, and tangential surfaces like Challenges and Best Efforts.
❌ Common myths
“Strava shaved off 0.10 km from my run!”
Inconceivable! The most we’ll ever round down by is 0.01 . Anything bigger could be a parsing issue – so if that happens, submit a ticket and we’ll look into it.
“If I don’t run 10.01, it won’t count!”
Depending on the device you use, you might need to go until your device screen says 10.01, but if it actually recorded 10.00 or higher, you’re golden. If your device says 10.00 but it actually recorded 9.999, you’ll see 9.99.
“This is just a Strava bug.”
It might seem like a bug, but as we’ve explained, it’s very much by design. We’d rather err on the side of caution than let the accuracy of our records start to dilute.
🔄 Why not change it?
We’ve talked about it! A lot! But here’s why we keep deciding not to:
The Strava tax would still be there, but in bigger, worse ways. Let’s say you run 9.99 miles 100 times in 2025 – if each one showed up as 10.00 miles, you’d think you ran 1,000 miles this year, but your total stats (and your Year In Sport) would show 999.
It would have to apply to everything. We’d need to change the display rules for display, storage, Challenges, Best Efforts, and so on. It would be an enormous lift that requires deprioritizing other parts of the product.
We just want to be transparent about the trade-offs and avoid creating even more confusion.
📬 So what now?
Strava Tax might not be going away tomorrow – but we’re continuing to explore better ways to explain it, make it more visible, and help athletes understand what’s really happening behind the scenes.
In the meantime, if your run comes up 0.01 short:
You’re not alone
It’s not personal, and
Yes, we’ve all done laps around the block to get the “full value.”
Strava will always aim to be a fair, neutral, and accurate ledger of record for your effort. That’s why – at least for now – death, taxes, and running parking lot circles to hit our mileage are three things that remain certain.
