Why is my phone battery draining so fast?

Most of the time it's a setting or an app, and you can sort it in ten minutes.

The answer in 2 lines. The usual causes are the screen, an app working in the background, a weak signal or location services. Open your phone's battery settings to see which apps use the most power. If the phone says the battery is degraded or needs a service, or it switches off with charge still showing, the battery is probably worn out. If the battery swells, or the phone gets too hot to hold, stop charging it and switch it off. If there is smoke or fire, get out and call 999. A faulty phone is the seller's responsibility, not the manufacturer's.

The first 3 steps

Open the battery section in your phone's settings. It lists the apps that have used the most power since the last charge.
Look for a battery health or battery status reading, if your phone has one. Note anything it says, such as a warning that the battery is degraded.
Install any system and app updates, then restart the phone.

Stop: danger

Swollen battery (the screen or back lifting or bulging): stop charging, turn the phone off, don't open the case and don't press on it. Contact the seller, the manufacturer or a qualified repairer (London Fire Brigade).
Phone too hot to hold, or smelling of burning: stop using it, unplug it if it's charging and put it on a hard surface away from anything that can burn.
Smoke or flames: get everyone out, close the door behind you and call 999.

The usual causes, and what you can do

Cause	What you can do
A very bright screen that stays on a long time	Turn on automatic brightness, set a short screen timeout and use dark mode
An app running in the background	Limit its background activity, update it, or delete it if you don't need it
Weak signal, often indoors or in rural areas	Use Wi-Fi where you can, and airplane mode where there's no signal at all
Location services always on	Allow location only while you're using the app
The first few days on a new phone	This is normal: the phone is copying and sorting your photos and data, and it settles down
A worn battery	Have it replaced (see below)

What you can do yourself, and where to stop

Turn on battery saver (low power mode) when you need the phone to last.
Switch off notifications and widgets you don't need. Some of them refresh all the time.
Use optimised charging or a charge limit if your phone has one. These features are designed to reduce battery wear.
Stop there: replacing a battery means opening the phone. On most models that's a job for the manufacturer or a qualified repairer, because a damaged lithium-ion battery can catch fire.

What not to do

Charging under a pillow, in bed or on a sofa. Trapped heat can start a fire (Electrical Safety First, London Fire Brigade).
Cheap unbranded or counterfeit chargers. Use the charger that came with the phone or a genuine replacement from a seller you trust.
Leaving the phone on charge overnight or while you're out, and using a phone that has been dropped, crushed or punctured.
Putting an old phone or battery in your household bin or recycling bin. If crushed, it can start a fire.

When to replace the battery, and who pays

Signs it's worn: the phone warns that the battery is degraded or needs a service, it switches off suddenly with charge still showing, or it no longer lasts a day despite the settings above.
Phone bought recently from a business: under the Consumer Rights Act 2015 you can reject faulty goods for a refund within 30 days. Within 6 months, the seller must repair or replace the item, and if that fails you can ask for a refund. After 6 months, you may have to show that the fault was there when you bought it (GOV.UK). Normal wear and tear isn't a fault.
Deal with the seller, not the manufacturer. Your rights apply to second-hand goods bought from a business too.
Outside your rights: ask the manufacturer or a qualified repairer for a written quote. A new battery usually costs much less than a new phone.

Citizens Advice's Return faulty goods page has a free online tool. Answer its questions about when and where you bought the phone, and it tells you what to ask the seller for. You can also send the seller its template letter after filling in your details.

Where you live: recycling the old battery or phone

Your council: on GOV.UK Recycling collections, enter your postcode to reach your council's page. It explains where to take mobile phones and other electricals, usually your local household waste recycling centre.
Buying a new phone: shops that sell electrical goods must give you a free way to get rid of the old one when you buy an equivalent new item, in store or through an alternative free take-back service (GOV.UK).
Help with a seller: the Citizens Advice consumer helpline is on 0808 223 1133, Monday to Friday, 9am to 5pm. Advisers can pass your complaint on to Trading Standards.

Good to know

Register your phone with the manufacturer: it is easier to hear about a safety recall or arrange a repair (Electrical Safety First).
Heat wears batteries out. Don't leave your phone in the sun or in a hot car.
Consumer law is similar in Wales, Scotland and Northern Ireland, but Citizens Advice has separate pages for each. In Scotland you have 5 years to make a claim, not 6.

In Norwich, Dev has to charge his phone twice a day. In the battery settings he finds that a game is running in the background, and the phone says the battery is degraded. He limits the game's background activity. The phone is two years old, so he gets a written quote from a qualified repairer for a new battery, and the phone lasts the day again.

A made-up story, for illustration.

Bobby

Sources, verification, confidence

Verified on 6 November 2026, for England. Confidence: high for the safety advice (swelling, chargers, charging in bed) and for the 30-day, 6-month and take-back rules; medium for the signs of a worn battery, which depend on the phone and how it is used. This guide covers common cases and is not a diagnosis.