Smartwatch tests are worth trusting only as far as you can see what they measure and how. Check what is measured, which reference device the watch is compared with, whether the lab bought its units or received them, and how the lab earns its money. The five labs below publish a method page and state their funding in their own words.
Inadviser has run no test in this category and names no best product. This page lists existing tests and what each says about itself. Each fact was read on the lab's own page; the link and the date read are beside it. Last page read: .
Existing tests compared
Labs are listed in alphabetical order. The order says nothing about quality. 6 parts below say "Not stated" because the lab's page did not say it. No score, ranking or product list is copied from any lab.
Existing smartwatches tests: what each measures, how it tests, how fresh it is, how it is funded and what it does not cover
Wrist heart rate, GPS accuracy, battery endurance and charging speed, wearability, and use across trail running, road running, climbing, skiing, backpacking and cycling.source, read
Instruments. Heart rate is compared point by point with an optical arm-worn sensor as the control. GPS is checked on a known two-mile course and in canyon terrain.source, read
Sample. Each watch gets two to three heart-rate comparison runs. The number of testers and watches is not stated.source, read
Who buys the units. The page says it independently buys and tests all products, with no freebies from manufacturers. The about page says it buys every product at retail and refuses free evaluation units.source, read
The page says the metrics were updated recently; no date is given.source, read
Run by a founder and editor-in-chief; part of a group with two sister review sites. Calls itself entirely reader-supported and earns money when readers buy through affiliate links.source, read
Display advertising is not addressed in the body text of the about page.source, read
Heart-rate variability, sleep scores and running fitness metrics are excluded because testers could not confirm their validity. The page says it is not medical advice.source, read
Heart rate, step count and route distance, altitude and GPS position; sleep tracking plausibility after three nights; battery in daily and sport scenarios; handling; drop, shock and scratch tests; data protection.source, read
Instruments. Heart rate is checked against a chest strap the page calls particularly precise. Testers walk or run across a sports field. No tolerance thresholds or GPS reference hardware are given.source, read
Sample. Three hobby athletes run the heart-rate and step tests; three experts each judge handling and communication. Units per product are not stated.source, read
Who buys the units. Products are bought anonymously in retail; the page says no press samples or prototypes are used.source, read
The test page is dated 15.04.2026; 14 new watches were added in April 2026. Devices have been tested since autumn 2022.source, read
A foundation that sells magazines, books and subscriptions; full results sit behind a payment.source, read
Manufacturers may advertise with its results through a logo licence or a special print run. How the foundation is funded is not stated on the page.source, read
Blood glucose and blood pressure accuracy are not part of this test. Pollutant testing is not part of the continuous tests.source, read
Smart functions, step counter accuracy, GPS accuracy over pre-measured distances, heart rate accuracy, workout tracking, battery life with GPS on and off, charge time, and display brightness and scratch resistance.source, read
Instruments. Heart rate is compared with a chest strap; steps with a manual count; GPS with pre-measured walking routes; brightness with a light meter; scratches with a Mohs hardness kit.source, read
GPS track on a fixed outdoor course, optical heart rate, sleep tracking, battery life, barometric altitude, running dynamics and blood pressure.source, read
Instruments. Optical heart rate is compared with two independent references worn together: a chest strap and an arm sensor. Sleep is compared with the mean of up to five reference devices worn the same night.source, read
Step count, distance, heart rate, battery runtime and charging, screen clarity, scratch resistance, smart features, and security and privacy. Blood oxygen is reported but excluded from the score.source, read
Instruments. Heart rate is compared with chest belts using an electrical method; distance is checked on routes of known length. Reference device models and lab conditions are not stated.source, read
Who buys the units. Which? says it buys all the samples it tests; its market analysts select the devices.source, read
The method page is dated 06 Jul 2026. It says heart rate and GPS standards were raised a few years ago.source, read
Which? describes itself as an independent not-for-profit charity with no shareholders, funded mainly by subscriptions.source, read
It shows no third-party display adverts. Some links earn affiliate commission, and companies can pay a fee to use its recommendation logo after a product meets its standard.source, read
Sleep tracking detail is linked separately. The page says wearables are not medical devices and does not give reference models or sample sizes.source, read
Which test to use for which decision
If you want to know whether a watch's heart rate was checked against a reference sensorUse the5krunner and OutdoorGearLab and TechGearLab and Stiftung Warentest. Each of these names a reference worn at the same time: two independent references at the5krunner, an arm sensor at OutdoorGearLab, and a chest strap at TechGearLab and Stiftung Warentest.
If you want a lab that says it bought its own unitsUse Which? and OutdoorGearLab and TechGearLab and Stiftung Warentest. Which?, OutdoorGearLab, TechGearLab and Stiftung Warentest each state on their pages that they buy products and do not use manufacturer samples.
If you want to know how sleep tracking was checkedUse the5krunner and Stiftung Warentest. The5krunner compares sleep with the mean of up to five reference devices, while Stiftung Warentest judges plausibility after three nights.
If you want to know about battery life and display testsUse TechGearLab and Which? and Stiftung Warentest. TechGearLab times battery with GPS on and off and tests display brightness, Which? times charging and runtime, and Stiftung Warentest uses daily and sport scenarios.
What this page does not do
It does not rank the labs or the products they test.
It states a lab's funding as the lab words it. It does not say any lab is paid or biased.
It has no affiliate links. Send a correction, with the page that shows it, through the corrections address.