Catalytic converter replacement cost

Price at a glance

Aftermarket vs original (OEM) parts

The converter contains precious metals (platinum, palladium, rhodium), which is why the part is expensive and why the choice of part makes the biggest difference to the bill.

In the UK, Bumper puts a mid-range hatchback such as a Ford Fiesta or Vauxhall Astra at about £700–£1,100 with an original part, or £350–£700 with an aftermarket one.

• Original parts are made to the factory specification and are the safest choice for passing emissions tests over the long term.
• Aftermarket parts cost much less. Quality ranges from as good as original to far worse, so pick a known brand with a warranty.
• US emissions rules. The EPA sets federal standards, but California (CARB) rules are stricter. CARB-compliant converters contain more precious metal and cost more, and universal-fit converters are not legal in CARB states. Check your state's rules before buying.
• Used converters from a breaker are cheaper but usually come without a guarantee, and some garages will not fit them.

Theft and anti-theft shields

Converters are stolen for their metal: AAA says thieves can sell one to scrap buyers for $100–$400, and Bumper notes some UK converters are worth upwards of £800 as scrap. Thefts have fallen since their peak: State Farm alone handled about 45,000 claims in 2022, and its claims dropped 74% in the first half of 2024 compared with a year earlier. Bumper lists models such as the Toyota Prius, Honda Element, Toyota Tacoma and Ford F-Series among common targets.

A stolen converter often costs more to replace than a worn one, because thieves cut through pipes and damage oxygen-sensor fittings: Bumper puts that extra damage at about $200–$500 in many cases.

Ways to protect your car:

• A vehicle-specific steel shield or cage, about $150–$400 fitted in the US. Bumper rates it the most effective deterrent.
• Marking or VIN etching on the converter, about $30–$100, which makes it harder to sell.
• Parking in a garage, or in well-lit, busy areas or covered by CCTV.
• An alarm with a tilt or vibration sensor.

If yours is stolen: you will hear a very loud roar when you start the car. Do not drive it. Report it to the police (in the UK, on the non-emergency number 101), tell your insurer, and have the car taken to a garage.

Emissions tests and the MOT

• US. AAA notes that most states require a working converter to pass emissions testing. A failing converter usually also turns on the check engine light.
• UK. In the MOT, emission control equipment fitted by the manufacturer that is missing, obviously modified or obviously defective is a major defect, which means an automatic fail. Exhaust emissions above the limits are also a major defect. ClickMechanic notes that driving without a catalytic converter can bring a fine of up to £1,000.

How to avoid overpaying

1. Make sure the converter is really the problem. A faulty oxygen sensor, a misfire or an exhaust leak can trigger the same fault codes. Ask the garage to fix any underlying fault before fitting a new converter.
2. Ask for an aftermarket quote alongside the original-part price, and check it is legal for your state or car.
3. Claim on insurance after a theft if the repair is well above your deductible.
4. Get two or three quotes for your exact car.

DIY or garage?