I plugged my watch in while I showered this morning, like I do every day, and it hit 100% before I dried off. That's the ritual. But charging isn't the problem. The problem is when I look down at mile 3 of my known 5-mile course and the watch says I've run 3.4. That's a lie, and I've spent the last seven years figuring out which ones tell it.
Related: Best Smartwatch for Running: GPS Accuracy, Tested
The best way to improve smartwatch GPS accuracy isn't buying a ~$400 Garmin, it's understanding the three things that actually cause the drift: how you wear the watch, what the sky looks like, and whether the watch is using the right satellite mode.
I've tested this across the budget range I actually review, from a ~$17 book to a friend's Garmin that costs more than my monthly rent. The fix is rarely the hardware. It's almost always the setup.
Pros:
- Most accuracy issues in cheap watches are fixable with a 30-second settings change
- A chest strap comparison will tell you within one run if your watch is lying or you're wearing it wrong
- The MorePro at ~$17 has a dedicated GPS mode that, once enabled, matches my known course within 2%
Cons:
- The default settings on most budget watches use a mixed GPS mode that's faster to lock but less accurate
- Battery life drops noticeably when you force GPS-only mode, sometimes by 40% on a long run
- The Apple Watch at ~$399 is the only one I've used that just works without any of these tricks, and you pay for that convenience
Compared to the Alternatives
The Garmin is the gold standard for GPS accuracy. I've borrowed my friend's, the one he won't shut up about, and ran my known course with it. It said 5.02 miles. My MorePro, after I fixed the settings, said 5.1. That's close enough for training, and the MorePro costs less than a pizza.
The Apple Watch is different. It's not just GPS, it's GPS plus cellular triangulation plus Wi-Fi positioning, all fused together. I've tested one for a week and it nailed my course at 4.98 miles. But you're paying for a phone on your wrist. The Garmin is the runner's choice because it gives you the accuracy without the distraction.
Here's the thing about cheap watches: they use the same GPS chipsets as the expensive ones, just older generations. The difference is how the software handles the data. That's fixable.
The Wrist Position Problem
I wear my watch on my left wrist, three fingers above the wrist bone, snug against the skin. That's the standard. But I've noticed something after years of testing: when I wear the watch loose, even slightly, the GPS accuracy degrades.
Not because the sensor moves, but because the watch loses skin contact and starts interpolating steps instead of measuring them.
That throws off the distance calculation.
One buyer, a guy named Tom who left a review on the MorePro, said his watch was telling him 5.5 miles on a 5K loop. He tightened the band and it dropped to 3.2. That's a bigger swing than any software fix. The watch was fine, his strap was the problem.
I've also tested wearing the watch on my right wrist during a run, just to see. The GPS trace was identical, but the heart rate data was garbage. The sensors are calibrated for one side, and the algorithm assumes the watch is on the non-dominant wrist. If you wear it on your dominant wrist, the step counting gets optimistic. It thinks you're walking when you're just moving your arm.
The Satellite Settings Fix
This is the big one. Most budget watches, including the MorePro, default to a "smart" GPS mode that uses multiple satellite systems to get a faster lock. It's faster, but it's less accurate. The fix is to go into the settings and force GPS-only mode. It takes longer to lock, maybe 30 seconds instead of 10, but the accuracy improves dramatically.
I tested this on my known course. With the default mode, the MorePro said 5.3 miles. With GPS-only, it said 5.1. That's a 4% error reduction from a single setting change. The Garmin doesn't need this because its default is already accurate, but the Apple Watch has a similar setting buried in the workout app.
The trade-off is battery. GPS-only mode drains the battery about 40% faster on a long run. My MorePro goes from 82% after a full day to maybe 60% if I do an hour-long run in GPS-only mode. That's still fine for a marathon, but you're not charging every day.
The Sky Problem and the Warm-Up Lock
GPS needs a clear view of the sky. That sounds obvious, but I've seen people run through tree-lined streets and wonder why their watch says they ran 5.8 miles when the course is 5.0. Trees and buildings bounce the signal. The watch gets confused.
The other issue is the lock time. If you start running before the watch has locked onto enough satellites, the first half mile is basically a guess. I've learned to wait until the watch shows the GPS signal indicator, usually a little icon that stops blinking, before I start moving. That takes 20 to 30 seconds on the MorePro, about 10 seconds on the Garmin.
One buyer, a marathoner named Sarah from Colorado, posted a review saying her watch was consistently adding 0.3 miles to her long runs. She started waiting for the GPS lock and the error disappeared. It's not a hardware issue, it's a patience issue.
The Chest Strap Ground Truth
I compare every watch against my chest strap. It doesn't use GPS, it measures my actual heart rate through electrical signals. When my watch says my average heart rate was 162 and my chest strap says 158, that's a 4-beat error. That's acceptable for training, but if you're doing zone training, a 4-beat error could put you in the wrong zone entirely.
The GPS accuracy and the heart rate accuracy are separate issues, but they interact. If the watch thinks you're running faster than you are, it predicts a higher heart rate. The algorithms are linked. Fixing the GPS drift often fixes the heart rate error too, because the watch is no longer trying to reconcile two conflicting data points.
The MorePro, after the GPS-only fix, showed 161 average heart rate against my chest strap's 158. That's within my acceptable margin, call it 2% error. The Garmin showed 159. The Apple Watch showed 157. All of them are usable, but the cheap one needed the settings fix to get there.
The App Connection and Why It Matters
The DaFit app, which pairs with the MorePro and a bunch of other budget watches, is the weak link. The QR code on the watch doesn't work. You have to find it in the manual. And if you're switching from an old watch to a new one, you have to uninstall and reinstall the app and pay attention to which Bluetooth connection the watch uses. I've figured this out through sheer stubbornness.
But once it works, the app gives you an incredible amount of health and activity data that's easy to understand. I get my steps, my sleep, my heart rate. The GPS trace is there too, and I can overlay it on a map to see where the drift happened.
That's how I confirmed the tree-line theory. The trace showed me running in a straight line through a park, then suddenly zigzagging when I hit the tree canopy.
The Garmin app is better, obviously. It gives you more data and the GPS traces are cleaner. But the DaFit app, once you get past the pairing nightmare, is surprisingly capable. For ~$17, WOW. I'm blown away by what these things can do.
Should You Buy a MorePro, a Garmin, or an Apple Watch?
If you're a runner on a budget, the MorePro with the GPS-only fix is the best value I've tested. You get 95% of the accuracy of a Garmin for less than 5% of the price. The battery dies after three months, that's a pattern I've seen across every cheap watch I've bought, but at ~$17 you can buy three of them for what one Garmin costs.
If you're a serious marathoner who needs reliable zone training, the Garmin is worth the money. It's the only watch I've used that I trust without checking the settings. The accuracy is consistent, the battery lasts a week, and the app doesn't make me want to throw my phone across the room.
If you want a smartwatch that happens to track fitness, the Apple Watch is the best of both worlds. It's the most accurate GPS I've tested, but it's also a phone on your wrist. You're paying for the integration, not the fitness tracking.
The best fitness watch is the one you'll actually wear every day, not the one with the most features on paper. For me, that's the MorePro, with the GPS settings fixed and the scrunchie band swapped in so my wrist stops sweating. It may not last a long time, but you get what you get for this price. And for ~$17, that's pretty good.
I'm currently testing a new budget watch that claims to have a dual-band GPS chip, which is usually reserved for ~$200+ models. If it works, that's going to change the whole budget landscape. I'll update this when I have the data.