Battery or new phone?

Replace the battery when the phone still has at least 18 months of security updates left and its battery health has fallen below 80 per cent; buy a new phone when support ends sooner or a second repair is due. Apple charges £85 to £119 for out-of-warranty battery service on an iPhone 13 to iPhone 18 Pro, against £323.49 for the cheapest new pick here, the Samsung Galaxy A57 5G.

The 18-month line is Compare Electronic's break-even: a £95 battery costs the same as 18.3 months of a £399 Google Pixel 10a's support period and 19.1 months of a Galaxy A57 5G's. Prices are Amazon UK at the time of writing (October 2026), and the phones match Best budget phone UK 2026.

How much does a phone battery replacement cost in the UK?

Apple's UK estimates for out-of-warranty battery service run from £65 on an iPhone SE to £119 on an iPhone 18 Pro, and most recent iPhones cost £95. Samsung UK publishes a battery price only for older Galaxy phones, £59 or £79; for the Galaxy A57 5G and Galaxy S26 Ultra it lists no standalone battery price, and its recommended screen repairs of £119 and £226 include a replacement battery where the service centre finds one needed.

Apple's figures are estimates: Apple inspects the phone to set the final fee, may add a delivery fee for a mail-in repair, and says Apple Authorised Service Providers set their own prices. Samsung lists an out-of-warranty inspection-only fee of £30 and describes its prices as recommended repair prices at its authorised service centres. A battery repair at Samsung's £119 rate costs 36.8 per cent of a new Galaxy A57 5G, against 23.8 per cent for a £95 iPhone battery set against a new Pixel 10a.

When does a phone battery need replacing?

At 80 per cent of its original capacity. That is the line Apple uses for AppleCare+, which covers battery service at no extra charge once capacity drops below 80 per cent, and the level Apple designs its batteries to hold: 500 complete charge cycles on iPhone 14 models and earlier and 1,000 on iPhone 15 models, about 16 months and 2.7 years at one cycle a day. Samsung UK lists a minimum endurance of 1,200 cycles for the Galaxy S26 Ultra.

A battery at 80 per cent gives roughly a fifth less runtime, so an iPhone 16, rated by Apple at 22 hours of video playback, drops to about 17.6 hours. On an iPhone the figure is under Settings, Battery, Battery Health, and iOS shows a service message when health is significantly degraded. Heat and long spells at full charge speed up wear, as covered in Is wireless charging bad for your battery?

A renewed phone is not a cure for a worn battery. Amazon UK states that Renewed phones have at least 80 per cent of original battery capacity, or 90 per cent on Renewed Premium, so a renewed iPhone can arrive at the very level that prompts a replacement. The trade-offs are in New vs renewed vs refurbished tech.

Battery or new phone: where is the break-even?

A £95 battery pays for itself if it keeps the old phone going 18.3 months against a new Google Pixel 10a, or 6.8 months against a renewed iPhone 16. Compare Electronic's break-even table divides each replacement phone's price by its months of security support left from October 2026, so every month the old phone keeps working saves that monthly cost.

An iPhone 15 owner has Apple support to at least September 2028, 23 months away, which clears every break-even in the table, so the £95 battery wins at £4.13 a month. An iPhone 13 owner staying on iPhone compares against the renewed iPhone 16: the £85 battery wins if the iPhone 13 lasts 6.1 more months. Android phones with years of support left change the sums, because the Galaxy A57 5G and Pixel 10a cost about £5 a month.

The maths ignores features. An iPhone 13 still runs iOS 27 but lacks Apple Intelligence and USB-C, which is the case for upgrading made in Should I upgrade my iPhone? Update end dates by brand are in How long do phones last?

Which phone should replace a worn-out one?

The Samsung Galaxy A57 5G is the best replacement for a phone not worth a new battery, at £323.49 on Amazon UK at the time of writing (October 2026). It has the lowest cost per month of support in the break-even table, £4.98, with up to 6 OS upgrades and up to 6 years of security updates, to about March 2032, and a typical 5,000 mAh battery that Samsung says lasts up to two days.

The Google Pixel 10a costs £75.51 more at £399 and buys a year more of support, to March 2033, at £5.18 a month. Buyers staying on iPhone should weigh the renewed iPhone 16 at £489.99 against a fresh battery in their current phone first.

Verdict

Replace the battery when the phone has 18 months or more of updates left and battery health is below 80 per cent: Apple charges £85 to £119, a fraction of any new phone. When support ends sooner, the Samsung Galaxy A57 5G at £323.49 costs £4.98 per month of support to about March 2032. The cheapest phones to own are ranked in Best budget phone UK 2026.