How do I fix a device that will not charge?

Working through charging faults in order — cable, adapter, socket, port — and the lint in the port that causes most of them.

Difficulty: beginner
Time: 30 min
Read: 2 min
Safety: caution

Short answer

Test a different cable and adapter first, then a different socket. If those are fine, the port is probably blocked with pocket lint — it compacts into a solid plug and stops the connector seating. Switch the device off and clear it carefully with a wooden toothpick.

Charging faults have four possible causes and they are easy to isolate by substitution. The most common one, by a wide margin, is compacted lint in the charging port of a phone that lives in a pocket.

Safety

Never use a metal object to clear a charging port — it can short the contacts or damage them permanently. Switch the device off first. Do not use a damaged cable or adapter, and do not use cheap unbranded chargers for lithium devices; poor-quality chargers are a genuine fire risk. A device that is hot, swollen or smells burnt should be stopped immediately and taken for assessment.

What you'll need

Alternative cable and adapter
Wooden toothpick
Torch
Compressed air (optional)

Step by step

Try a different cable.Cables fail internally at the strain points near each end, and the failure is often invisible. This is the single most common cause.
Try a different adapter and a different socket.Substitution isolates the fault. Change one thing at a time.
Check whether the device charges from a computer's USB port.It will be slow, but it tells you whether the device or the charger is at fault.
Look into the charging port with a torch.You are looking for compacted grey lint filling the bottom of the port. It is extremely common and prevents the connector seating fully.
Switch the device off and clear the port with a wooden toothpick.Wood, not metal. Scrape gently along the bottom and sides and lift the lint out. It often comes out as a solid plug.
Try charging again once cleared.In many cases the connector now clicks in properly for the first time in months.
Restart the device if it still will not charge.A forced restart clears a stuck charging state, which does occasionally happen.
Check for physical damage to the port or a swollen battery.A swollen battery — a case that no longer sits flat, or a lifting screen — means stop using it and get it assessed. Do not charge it further.

Tips

Wireless charging bypasses a faulty port entirely, which is a useful diagnostic as well as a workaround.
Cheap unbranded chargers are a false economy and a real fire risk with lithium batteries. Use a reputable one.
If a device charges only at a particular cable angle, the port or the cable is damaged. Continuing to wiggle it makes the damage worse.

Common mistakes

Using a metal pin to clear the port — It can short or damage the contacts permanently, turning a lint problem into a repair.
Assuming the device is faulty — Cables fail far more often than devices. Substitute the cable first.
Continuing to charge a swollen battery — A swollen lithium battery is a fire risk. Stop using the device and get it assessed.

Questions people ask

Why has my phone stopped charging?

Most often a failed cable, or compacted lint in the charging port preventing the connector seating. Test a different cable first, then look into the port with a torch.

How do I clean a charging port?

Switch the device off and scrape gently with a wooden toothpick along the bottom and sides. Never use anything metal. The lint usually comes out as a single compacted plug.