How much does an exhaust replacement cost?
A new exhaust in the UK usually costs somewhere between £150 and £1,200 fitted. A single back box on a small hatchback can be around £150 to £350, while a full system on a larger or performance car can run past £1,000. The exact figure depends on your car, the material used and your local garage, so treat any quote as a starting point.
An exhaust does more than make noise. It carries hot, toxic gases safely away from the engine and out behind the car, quietens the sound and helps the engine run cleanly. Because it sits underneath the car in the spray, salt and heat, it is one of the parts most likely to rot or crack over the years, and eventually it needs replacing.
The trouble with a simple question like this is that a “new exhaust” can mean anything from a small rear silencer to a complete system from the engine back. That is why quotes vary so widely. This guide breaks the job down so you can understand where your own car is likely to sit.
Part of the exhaust, or the full system?
A modern exhaust is built in sections that bolt or clamp together. From the engine backwards you typically have the front pipe and catalytic converter, then one or more middle sections with a silencer, and finally the back box, which is the rear silencer you can usually see poking out at the bumper.
The good news is that a garage can normally replace only the section that has failed. If the back box has rotted through but everything else is sound, you pay for a back box, not a full system. This is the single biggest reason two people can be quoted such different prices for “an exhaust”.
Back box versus cat-back
Two phrases you will hear are “back box” and “cat-back”. A back box replacement is just the rear silencer. A cat-back system means everything from behind the catalytic converter to the tailpipe, so the middle section and the back box together. Cat-back is a bigger job with more parts, so it costs more.
The catalytic converter itself is a separate story. It is an expensive emissions part and is priced on its own, so if a garage mentions the “cat” it is worth asking whether that is included in any figure they give you.
Typical UK costs
The ranges below are broad on purpose. They reflect what UK drivers commonly pay, but the right number for your car depends on the make and model, the material and your local labour rates. Always treat these as a guide, not a fixed price.
| Job | Typical UK range (fitted) |
|---|---|
| Back box on a small hatchback | £150 to £350 |
| Back box on a family car | £220 to £400 |
| Middle / mid section | £200 to £500 |
| Full system (small car) | £350 to £600 |
| Full system (larger or performance car) | £600 to £1,200+ |
On top of the parts, most of the cost is fitting time. Independent garages commonly charge around £40 to £120 an hour, with dealer workshops higher still, and rates in London and the South East tend to sit above those in the North and rural areas. A straightforward back box can be a quick job, while a rusted-in full system that fights every bolt takes far longer.
Why the car and the material matter so much
Two things drive the price more than anything else. The first is the car. A common small hatchback has cheap, widely available exhaust parts, while a large SUV, a diesel with extra emissions plumbing or a performance model can have parts that cost several times as much. Awkward routing and heat shields also add labour.
The second is the material. Mild or aluminised steel is cheaper but rots faster, so it may need doing again in a few years. Stainless steel resists rust and lasts much longer, but you pay more at the outset. If you plan to keep the car a long time, the dearer stainless option can work out cheaper over its life.
Signs your exhaust is failing
Exhaust problems usually announce themselves through sound. Watch and listen for:
A louder, droning note. If the car has suddenly got noticeably noisier, especially a deep drone under acceleration, a silencer has probably corroded through.
A blowing or rasping sound. A sharp chuffing or rasp, often worse when cold, points to a leak at a joint or a hole in a pipe. Leaks let gases escape before the silencer and can also let fumes near the cabin.
A rattle from underneath. A loose heat shield or a silencer that has broken away from its mountings will rattle or knock, particularly over bumps or at idle.
A drop in performance or economy, or a warning light. On modern cars a leak upstream can upset the sensors and light the engine management lamp. If your car also feels flat, our guide on why a car loses power may help you narrow it down.
Getting a fair price
Because an exhaust quote depends on which section you need, the best move is to have a garage put the car on a ramp and show you what has actually failed. Ask whether a single section will do, whether stainless is an option and whether the price includes fitting. It is sensible to get more than one quote for anything beyond a simple back box.
A tired exhaust rarely fixes itself, and a small leak tends to grow. Catching it early often means replacing one cheap section rather than a whole system later. If you are booking work anyway, it is a good moment to think about how you pick a workshop, and our guide on how to choose a good garage walks through what to look for.
Prices move over time and every car is different, so use the figures here to sense-check a quote rather than as a promise. A quick inspection and an honest conversation with a trusted garage will always give you a truer number than any online estimate.
Key takeaways
- A back box on its own is the cheapest job, often £150 to £350 on a small car.
- A full exhaust system is far more, typically £350 to £1,200 or more depending on the car.
- Stainless steel lasts longer than mild steel but usually costs more up front.
- Loud droning, a blowing rasp or a rattle underneath are the classic signs of a failing exhaust.
Frequently asked questions
Can I replace just one part of the exhaust?
Often yes. Exhausts are made in sections, so a garage can usually replace just the back box or the corroded middle section rather than the whole system. That keeps the cost down, though very old or one-piece systems sometimes have to be done in full.
Will a blowing exhaust fail the MOT?
It can. An exhaust that is leaking, insecure or noticeably louder than the manufacturer intended is an MOT failure item, and a leak near the cabin can also let fumes in. It is worth sorting before your test rather than after a fail.