Alternator · 2026
Alternator replacement cost.
Replacing an alternator costs £170–£600 fitted at a UK independent garage in 2026, depending on the car and whether the unit is reconditioned or new. Before authorising one, have the charging system tested: a slipping auxiliary belt or a corroded earth strap produces exactly the same symptoms as a failing alternator and costs a fraction as much to fix.
A battery warning light that stays on while you are driving points at the alternator rather than the battery. The flat battery is usually the symptom, not the fault.
What it costs, by route
| Route | Typical cost | What it involves |
|---|---|---|
Reconditioned unit | £170–£380 Most common route, most cars | A remanufactured alternator with new brushes, bearings and regulator, warrantied. Considerably cheaper than new and the standard independent-garage choice. |
New aftermarket unit | £240–£520 No recon unit available, or you want longer warranty | A new unit from an established manufacturer. Typically the middle option on price and the easiest to source quickly. |
Smart-charging / stop-start car | £300–£600 Car has intelligent charging or a battery sensor | The new unit has to be coded to the ECU and the battery registered, which adds diagnostic time on top of the fit. |
Auxiliary belt at the same time | add £60–£140 Belt is worn or has been contaminated | The belt comes off to reach the alternator anyway. If it is glazed, cracked or oil-soaked, replacing it now costs only the part. |
Independent-garage prices for 2026, including VAT. Main dealers typically charge 30–50% more, and London and the South East sit at the top of each range.
Before you authorise an alternator
- Ask for a charging-system test, not just a battery test. A slipping or glazed auxiliary belt, a corroded earth strap or a failed battery sensor all mimic a dying alternator and cost £30–£120 to put right.
- If the battery has been repeatedly run flat, have it tested too. A deeply discharged battery can be damaged beyond recovery, and a new alternator will not fix it.
- On a stop-start car, confirm the quote includes coding the new unit and registering the battery. Skipping that step leaves the charging system running the wrong profile.
What will it cost near you?
£170–£600 is the UK average. See what your local garages charge.
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Good question
Questions Okay gets asked a lot
How much does it cost to replace an alternator in the UK?
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Expect £170–£600 fitted at a UK independent garage in 2026. A reconditioned unit — the usual choice — is £170–£380 fitted, a new aftermarket unit £240–£520, and a car with smart charging or stop-start £300–£600 because the new alternator has to be coded to the ECU. If the auxiliary belt is worn, replacing it at the same time adds only £60–£140 because it has to come off anyway.
Can I drive with a failing alternator?
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Only briefly, and not at night or in the rain. Once the alternator stops charging, the car is running purely on the battery — typically 30 to 60 minutes of driving, less with lights, wipers and heated screens on. When the battery goes, the engine stops, potentially in traffic. If the battery warning light is on while you are driving, head straight to a garage or home, and switch off every electrical load you can do without.
Is it the battery or the alternator?
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The clearest tell is when the warning light appears. A battery problem shows up when starting — slow cranking, a click, a jump start that then runs fine. An alternator problem shows up while driving — the battery light stays lit, headlights dim at idle and brighten when you rev, and the car goes flat again shortly after a jump start. Any garage or parts shop can test the charging output in a few minutes, and that test is worth doing before replacing either part.
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