Apple's MacBooks are the only current laptops to meet or exceed their makers' battery life claims, British testing publication Which? found in a comparison of several major brands.

The site used three different MacBook models including the 13-inch 2016 MacBook Pro, and found that while Apple claimed 10 hours on average, the real-world figure was 10 hours and 15 minutes, easily outranking computers by Asus, Acer, Dell, HP, Lenovo, and Toshiba. A 13-inch MacBook Pro in fact lasted for 12 hours.

The evaluation process involved draining each laptop repeatedly in several different every-day tasks, such as watching movies, or loading websites over Wi-Fi.

In some cases there were major discrepancies between results and marketing. HP's Pavilion 14-al115na, for instance, is claimed to run for 9 hours, but in practice lasted just 4 hours and 25 minutes. Similarly, the Dell Inspiron 15 5000 managed just 3 hours and 58 minutes despite nominally being capable of 7 hours.

"It's difficult to give a specific battery life expectation that will directly correlate to all customer usage behaviors because every individual uses their PC differently — it's similar to how different people driving the same car will get different gas mileage depending on how they drive," Dell told Which? in trying to explain the gap.

HP meanwhile said that its battery testing "uses real life scripts and runs on real applications like Microsoft Office," and that particular specifications — like resolution — can impact power consumption.

The Which? results are in some ways actually more conservative than ones generated by U.S. magazine Consumer Reports when it retested Apple's 2016 MacBook Pros. In the latter case, one unit managed nearly 19 hours.