What GPS accuracy actually means on a running watch

Two specifications separate running watches from each other, and they pull in opposite directions. Understanding the trade between them is most of what you need to choose one.

The first is GPS accuracy, and the term to look for is dual-band, sometimes called multi-band or L1+L5. A single-band receiver listens on one satellite frequency. A dual-band receiver listens on two, which lets it identify and reject signals that have bounced off a surface before reaching your wrist. That reflection — multipath, in the jargon — is the reason a recorded track sometimes wanders through the buildings beside the road rather than along it.

The crucial point is where this matters. In open countryside a single-band watch is already accurate to within a few metres and dual-band buys you almost nothing. Between tall buildings, under trees, or in a narrow valley, it is the difference between a track you recognise and one you do not. If most of your running is urban, this is the single specification worth paying extra for. If it is rural, it is close to irrelevant and you should spend the money elsewhere.

The second specification is battery life, and dual-band is expensive for it. Watches quote figures per mode, and the modes are not comparable between makers. Smartwatch mode means the watch is not recording an activity — that is the big headline number, and it is the least useful one. GPS mode figures drop sharply, and dual-band GPS drops them further again, sometimes by half. Compare like with like: GPS-mode figures against GPS-mode figures, and treat the smartwatch headline as marketing.

Screen technology sits underneath both. AMOLED panels look dramatically better in a shop and consume meaningfully more power. Memory-in-pixel screens look duller indoors, are perfectly readable in direct sunlight without a backlight, and are the reason some watches quote two weeks where others quote five days. Neither approach is better than the other; they are different answers to the same question. Decide which side of that trade you want before you stand in front of a display, because the display will decide for you.

One last thing to check before buying anything in this category, because it is easy to miss and expensive to discover: whether the training analysis requires a subscription. Several manufacturers now place recovery, training load and race prediction behind a monthly fee. Over four years of ownership that can quietly exceed what the watch itself cost, and it does not appear anywhere on the specification sheet.