Catalytic converter replacement cost UK
Typical price fitted at an independent garage for a type-approved aftermarket cat — the part is most of the bill.
- Genuine OEM cat: £500 – £1,500
- Rear lambda sensor instead: £80 – £200
- Labour is only £100 – £250 of it
A catalytic converter replacement costs £250 – £700 fitted at an independent garage using a type-approved aftermarket cat, and £500 – £1,500 with a genuine OEM part — but the most common trigger, fault code P0420, is often cured by an £80 – £200 lambda sensor instead. Diagnose before you buy. Pick your car below for your range, then compare live prices from garages near you.
Price ranges are estimates — final quotes come from garages. Compare live quotes from local garages →
Catalytic converter cost by make and model
| Model | Aftermarket, fitted | Genuine OEM, fitted | Time |
|---|---|---|---|
| Ford Fiesta | £250–£400 | £500–£850 | 1–2 h |
| Ford Focus | £270–£450 | £550–£950 | 1–2 h |
| Vauxhall Corsa | £250–£400 | £500–£850 | 1–2 h |
| Vauxhall Astra | £270–£450 | £550–£950 | 1–2 h |
| VW Golf | £280–£480 | £600–£1,000 | 1–2 h |
| VW Polo | £250–£400 | £500–£850 | 1–2 h |
| Nissan Qashqai | £300–£520 | £650–£1,100 | 1.5–2.5 h |
| Nissan Juke | £280–£480 | £600–£1,050 | 1.5–2.5 h |
| Mercedes A-Class | £380–£650 | £800–£1,400 | 1.5–2.5 h |
| BMW 1 Series | £380–£650 | £800–£1,400 | 1.5–2.5 h |
| BMW 3 Series | £400–£700 | £850–£1,500 | 1.5–2.5 h |
| Audi A3 | £350–£600 | £750–£1,300 | 1.5–2.5 h |
| Honda Civic | £300–£520 | £650–£1,100 | 1–2 h |
| Toyota Yaris | £300–£550 | £700–£1,250 | 1–2 h |
| Kia Sportage | £300–£520 | £650–£1,100 | 1.5–2.5 h |
Independent garage prices, gaskets and fitting included; type-approved aftermarket parts in the first column. Hybrid Yaris cats carry a premium — their low-wear converters are rich in precious metals, which is also why thieves like them. Cats integrated into the exhaust manifold (some German engines) cost more in labour. Main dealers typically charge around 50% more on the same part class. Final quotes come from garages.
What affects the price
The metal inside is the price tag. A catalytic converter is a honeycomb coated with platinum, palladium and rhodium — metals that trade like bullion. That’s why the part is £150–£1,200 while fitting it is £100–£250, why OEM cats cost two to three times aftermarket ones, and why the whole assembly is worth stealing. Almost nothing else on your car has a scrap value; this does.
Where the cat sits decides the labour. A cat bolted into the exhaust line under the floor is an unbolt-and-swap job at the bottom of our time column. One cast into the exhaust manifold — common on newer downsized engines — means working in the tightest part of the bay, and seized studs on a decade of heat cycles can stretch any estimate. A fair quote on an older car says “plus extra if the fixings fight us” out loud.
Sensors ride along. The lambda sensors thread into or beside the cat, and they rarely survive removal after years of heat — many garages quote a sensor or two as a matter of course. That’s legitimate; £80–£200 per sensor is the going rate fitted. What isn’t legitimate is skipping the sensor test before condemning the cat in the first place, which brings us to the most profitable fault code in Britain.
P0420: the fault code that sells catalytic converters
“Catalyst system efficiency below threshold” — P0420 — is among the most-Googled fault codes in the UK, and the moment it appears, somebody will quote you for a new cat. Sometimes they’re right. But the code doesn’t measure the cat directly: it compares the signals of the lambda sensor before the cat and the one after it. A lazy, aged rear sensor can produce the exact same code with a perfectly healthy converter — and it costs £80–£200 instead of £250–£700. Work the ladder in order:
| Check, in order | What it looks like | Typical cost |
|---|---|---|
| 1. Live-data diagnosis | Rear sensor voltage read warm — steady is healthy, mirroring the front sensor is not | £40 – £60 |
| 2. Exhaust leak before the rear sensor | Blowing joint or cracked flexi skews readings; audible chuff on cold start | £45 – £140 |
| 3. Rear lambda sensor | Aged or sluggish sensor — the classic false accuser | £80 – £200 fitted |
| 4. Engine running rich / misfiring | The thing that killed the cat and will kill the next one — fix first | £60 – £300 |
| 5. Catalytic converter | Confirmed only after 1–4 — efficiency genuinely gone | £250 – £700 aftermarket |
The question that keeps the quote honest is the ladder in one sentence: “was the rear lambda sensor tested before condemning the cat?” A garage that read the live data will tell you what the sensor traces showed; a garage that scanned the code and reached for a price list will change the subject. On a £700 decision, that one question is the best-paid sentence you’ll say all year — and if you drive a diesel, note that your equivalent of this entire page is the DPF, with its own codes and its own ladder.
Cat theft: who gets targeted and what actually helps
Catalytic converter theft became a national sport for one reason: a thief with a battery saw can be under a car and gone in under two minutes, carrying £100–£500 of precious metals in scrap value. Hybrids are the prize — their cats work less (the engine is off half the time), so the metals stay rich and unworn. The Toyota Prius is the most stolen cat in the UK by a wide margin, with older Auris and other hybrids close behind; tall SUVs get hit too, simply because nobody needs a jack to get under them. If you’ve come to this page the morning after, you’re not pricing a repair so much as a claim — see below.
What helps, honestly ranked: parking that denies access beats every gadget — garage, wall-side, or nose-in against something low. A bolt-on cat shield or cage (£90–£200 fitted) turns a two-minute job into a noisy ten-minute one, which is usually enough. Forensic marking kits deter resale more than theft. And after a theft, the insurance route is normal — cat theft is a standard comprehensive claim — but weigh the excess and premium impact against a £250–£700 aftermarket replacement paid in cash; on older cars the cash route often wins. Whichever way you go, have the replacement’s fixings welded or security-bolted, because stolen-once cars get revisited. Run your reg through our checker to see what your exact model’s replacement costs before you talk to the insurer.
Aftermarket, OEM and the law: what’s legal to fit
The law here is simple and worth knowing before anyone quotes you. A replacement cat for road use must be type-approved for your vehicle — quality aftermarket cats carry that approval and are entirely legal, at a third of the OEM price. What’s not legal is driving without one: removing a cat, fitting a “decat pipe” or gutting a stolen-cat stub and welding straight pipe is an automatic MOT emissions failure and an offence in its own right, with fines to match. “Sports cats” below the approved spec are for track cars, whatever the listing says.
So when does genuine OEM earn its two-to-three-times premium? Keeping the car long-term, emissions-sensitive engines that run close to the limits, and warranty or lease situations that demand it. For an older car heading toward its later owners, a type-approved aftermarket cat that passes the MOT emissions test is the rational buy — the test doesn’t award style points for the logo on the shell. What matters either way is the paperwork: keep the invoice naming the part and its approval, because the next MOT tester, buyer or insurer may reasonably ask.
Diagnosis — tap test plus live-data check ruling out the sensors: free with the job. Type-approved aftermarket cat: £190. Labour, 1.5 hours including one seized stud: £90. New gaskets and clamps: £20. Post-fit emissions check: £30. Total: £330 — mid-table for the aftermarket column.
The same job in genuine OEM: £650–£1,100. And if the fault had been the rear lambda sensor rather than the rattle, the bill would have stopped at about £110 — which is why the tap test and sensor trace come before anyone orders a cat.
Where to get it done: independent, dealer or exhaust specialist
| Independent garage | Main dealer | Exhaust specialist | |
|---|---|---|---|
| Aftermarket cat, typical | £250 – £700 | Usually OEM-only, £500 – £1,500+ | Often the keenest price — it’s their trade |
| Best for | Diagnosis-first jobs, sensor work | Warranty and lease cars, manifold-cat engines | Post-theft rebuilds, welded fitting, shields |
| Worth asking | “Show me the rear sensor trace” | Goodwill on known cat failures — it exists | Security bolts or welding on the new cat |
Exhaust specialists are the third player worth knowing here — cats, pipes and welding are their entire day, their part prices reflect volume, and post-theft work (mangled pipework, custom sections) is routine for them where a general garage improvises. For a straight swap or a theft rebuild, get one of their quotes into the comparison. Compare cat replacement prices from garages near you →
Six signs of catalytic converter trouble
- Engine light with P0420. The headline act — but remember what it actually measures: the disagreement between two sensors. Climb the ladder above before anyone orders the expensive rung. £40 – £60 diagnosis first
- A rattle from underneath, worse on startup. The ceramic honeycomb has broken up and the pieces are shaking in their shell. The tap test — a gentle knock on the cat with the car cold — makes it unmistakable. This one really is the cat. £250 – £700 aftermarket
- Rotten-egg smell. Sulphur compounds the cat should be converting, escaping untreated — a struggling converter or an engine running rich enough to overwhelm it. Smell plus code moves the cat up the suspect list. Diagnose — cause may be £60, not £600
- Sluggish uphill, gutless at speed. A melted or collapsed core chokes the exhaust like a plugged chimney — the engine breathes out through a straw. Severe cases barely pull above town speeds. Back-pressure test confirms it, £40 – £60
- MOT emissions failure. How most tired cats are actually caught. But a cold engine, stale service items or a lazy sensor fail the same test — see the honest fix order in the save section below. £0 – £700 depending on the real cause
- The car is suddenly, shockingly loud. The overnight version: your cat has been stolen and the exhaust now ends mid-car. Don’t drive far — fumes and heat where they shouldn’t be — and read the theft section above before ringing anyone. £250 – £700 + security fitting
A dead cat is usually a symptom — fix the killer first
Here’s the truth that saves second cats: converters rarely die of old age. A healthy engine’s cat can outlast the car — 150,000 miles and beyond — because nothing inside it moves or wears. When one dies young, something killed it, and fitting a new cat without finding the killer is buying the same funeral twice. The suspects: a misfire pumping unburnt fuel into the cat, which ignites inside and melts the honeycomb — the fastest killer, days not months. Oil burning past worn rings or valve seals, glazing the catalyst surfaces until they can’t react. Coolant sneaking in through a failing head gasket, poisoning the coating. And a diet of short cold trips that never lets the cat reach the 400°C it needs to work and self-clean.
The practical consequence is blunt: if your cat failed and the engine has any of those habits, the engine gets fixed first or the new cat’s warranty is a fiction — most cat manufacturers explicitly void cover where an underlying fault killed the part. A garage on your side will say this unprompted; it’s less profitable than nodding and fitting. And the half-value rule applies at the top end: an OEM cat plus the engine work that caused its death can pass half the value of an older car, at which point the honest conversation is the one our checker starts — the full number for your exact car, next to what the car is worth.
How to pay less for a catalytic converter
Spend £50 on diagnosis before £500 on parts. The rear-sensor trace, the leak check and the tap test between them settle most P0420s — and roughly none of them require buying a converter to find out. The most expensive words in this repair are “let’s try a cat and see”.
Beat the emissions fail the cheap way first. MOT emissions tests are run on the engine as presented: a proper warm-up drive beforehand, fresh oil and plugs if a service is overdue, and a long motorway run to heat the cat through have passed thousands of borderline cars. If it still fails with everything else healthy, then the cat has earned the blame.
Buy type-approved aftermarket unless you have a reason not to. Same legal standing, same MOT pass, a third of the price. The OEM premium buys longevity headroom and logo — rational on a keeper, wasted on a car with three owners left in it. Whichever you buy, keep the invoice naming the approval.
After a theft, price both routes before claiming. Get the cash quote for an aftermarket cat with security fitting, then compare it against your excess plus the premium hit. On older cars the cash route wins surprisingly often — and either way, the shield or welded fixings go on with the new cat, not after the second theft.
Compare live catalytic converter prices from garages near you — book online, pay when the job’s done.
Compare live quotesFAQ
How much does a catalytic converter replacement cost in the UK?
£250–£700 fitted with a type-approved aftermarket cat at an independent garage, or £500–£1,500 with a genuine OEM part — the precious metals inside make the part the bill, with labour only £100–£250. If the trigger was fault code P0420, an £80–£200 rear lambda sensor is the cheaper suspect to test first.
Does fault code P0420 mean I need a new catalytic converter?
Not automatically — P0420 compares two sensor signals, and an aged rear lambda sensor produces the same code with a healthy cat for £80–£200 instead of £250–£700. The honest order: live-data diagnosis, exhaust leak check, rear sensor, engine faults, and only then the converter itself.
Can I drive with a bad catalytic converter?
Physically, often yes for a while — legally and financially it’s a poor plan. You’ll fail the MOT emissions test, fuel economy drops, and a collapsing core can choke the engine or overheat under the floor. A rattling or blocked cat should be booked promptly; a stolen one shouldn’t be driven beyond the garage.
Why are catalytic converters stolen?
The platinum, palladium and rhodium inside carry £100–£500 in scrap value, and a battery saw removes a cat in under two minutes. Hybrids are the prime target — their cats wear less, so the metals stay rich — with the Toyota Prius the most stolen in the UK by a wide margin, and tall SUVs hit for easy access.
How long does a catalytic converter replacement take?
1–2 hours for a cat bolted into the exhaust line, 1.5–2.5 where it’s integrated into the manifold or the fixings have seized after years of heat cycles. Post-theft jobs run longer if the thief’s saw took pipework with it — exhaust specialists handle those rebuilds routinely.
Are aftermarket catalytic converters legal in the UK?
Yes — provided they’re type-approved for your vehicle, which quality aftermarket cats are. They cost roughly a third of OEM and pass the same MOT emissions test. What’s illegal is no cat at all: decat pipes and gutted shells are an automatic emissions fail and an offence, regardless of how the listing words it.
What’s better: OEM or aftermarket cat?
Aftermarket type-approved for most cars — same legality, same test, a third of the price. OEM earns its two-to-three-times premium on keepers, emissions-marginal engines and warranty or lease cars that require it. The MOT tester measures gases, not logos; keep the invoice naming the part’s approval either way.
What kills catalytic converters?
Misfires above all — unburnt fuel ignites inside and melts the honeycomb in days. Then oil burning past worn rings, coolant from a failing head gasket poisoning the coating, and a diet of short cold trips that never lets the cat reach working temperature. A cat on a healthy engine routinely outlasts the car.
Why does my car smell of rotten eggs?
Hydrogen sulphide — sulphur compounds the cat should be converting but isn’t, either because it’s failing or because the engine is running rich enough to swamp it. Occasional whiffs after hard running can be normal; a constant smell plus a warning light earns the £40–£60 diagnosis.
Will a bad cat fail the MOT?
Through the emissions test, yes — that’s how most are caught. But so will a cold engine, stale plugs and oil, or a lazy sensor: many “cat failures” pass after a proper warm-up and overdue service. Exhaust the cheap causes before the expensive conclusion; the retest doesn’t care which fixed it.
How long do catalytic converters last?
100,000–150,000 miles is routine and many outlast the car — nothing inside moves, so nothing wears. Premature deaths are murders, not natural causes: misfires, oil, coolant or endless cold starts. Which is why a young cat’s failure should always trigger the question “what killed it?” before a replacement goes in.
Does insurance cover catalytic converter theft?
Yes — it’s a standard comprehensive claim, typically including the mangled pipework. Whether to claim is arithmetic: excess plus premium impact versus a £250–£700 aftermarket replacement in cash, which often favours cash on older cars. Either way, fit the shield or security bolts with the new cat — stolen-once cars get revisited.