iPhone and Android users warned hugely popular setting is draining their batteries

Dark mode is easy on the eyes – but not too easy on your phone battery, a new study has found. Also called night mode, the function tones down colours, makes black text white and adds a dark background. Everything from Apple and Android operating systems to laptops and social media websites has introduced a toggle to switch dark mode on.

Around eight in 10 Android smartphone owners use a light-on-dark colour scheme day to day. But while many believe that the display conserves battery life because it generates less light, this isn’t exactly the case, BBC researchers found. Many phones use OLED screens, where every pixel is individually lit.

When the panel displays the colour white, all the pixels are turned on, sapping energy. Darker pixels need less energy to be displayed. So while dark mode does reduce energy consumption, BBC researchers found that 80% of smartphone users crank up the brightness to compensate for the darker display.

This created a ‘rebound effect’ as people waste more energy than they would if they had their phone on light mode, the research published yesterday said. People who were using light mode were found by the broadcaster to be less likely to fiddle with their brightness settings.

Rather than rely on dark mode to keep battery percentages high, researchers recommend keeping the brightness as low as possible. BBC R&D engineer Zak Datson said: ‘It’s great that lots of us are looking for ways we can be more environmentally friendly.

‘But some of the most common sustainability recommendations are overly simplistic, to the point that many simply don’t work in the way they’re intended – or in the case of dark mode, actually end up using more energy. ‘What we need is a better understanding of what exactly causes our devices to consume energy when we spend time online.’.

A 2021 study similarly found that dark mode isn’t a surefire way to extend battery life. When a phone was set to max brightness and displayed a Google app set to dark mode, it would use 42% less power than in light mode. Yet when the brightness was at 50%, dark mode would only use 9% less power.

As night mode is a relatively new piece of tech, research on it is spotty at best – especially on its supposed benefit on eye health, experts say. Eyes have to work harder when looking at dark backgrounds in light environments, which can lead to fatigue.

Dark mode does lower the amount of blue light screens create, a type of harsh light that boosts attention but slows the production of melatonin at night. While digital eye strain is real, scientists aren’t wholly convinced blue light is solely to blame.

If strain is a concern, experts recommend keeping the brightness low and stepping away from screens every now and then. Get in touch with our news team by emailing us at webnews@metro.co.uk. For more stories like this, check our news page. Arrow MORE: Apple release new iPhone 16e but there’s a major difference in latest model.

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