https://www.cnet.com/news/smartwatch-step-counter-and-distance-tracker-accuracy/

While the Apple Watch takes the accuracy crown once it's calibrated, it's also worth saluting the three devices that delivered the most reliable out-of-box results in our test. If you want to be certain of your exact distance and aren't interested in calibrating your device, the Garmin Vivosmart , the Samsung Gear S and the Garmin Vivoactive are your best choices -- for now.