How Much Does a Catalytic Converter Cost? (2021)

How much does a catalytic converter cost in white text over the image of a car exhaust manifold

Urban pollution in the UK contributes to around 40,000 excess deaths each year! Fortunately, the catalytic converter (also known as the ‘cat’) helps minimise your car’s emissions. Unfortunately, when things go wrong, your catalytic converter can cost a small fortune to repair.

But why is that? And how much does a catalytic converter cost?

In this guide, we’ll cover catalytic converter cost, purpose and what you can do to keep it in top condition. 


How Much Does a Catalytic Converter Cost? 

Your catalytic converter price depends on what car you drive. In the UK, the average replacement costs between £150 to £800, but it can cost over £1,000 for some high-end vehicles!  


City cars & Hatchbacks – £150 – £250

Saloons & Estate Cars – £300 -£400

Sports & Deluxe Cars – £500+  


But why does a catalytic converter cost so much?

Well, it’s not cheap to build. Your ‘cat’ uses Platinum, Palladium or Rhodium as a catalyst – and those precious metals are hard to find! On average, platinum costs £28 a gram, Palladium a staggering £55 a gram and Rhodium an eye-watering £570 a gram! And, as the prices of precious metals constantly fluctuates, these numbers are hard to predict. When you factor labour in as well, it’s very hard to keep your catalytic converter cost under control. You can browse catalytic converter replacement parts on Eurocarparts to get an idea of current prices.  


Heavily smoking exhaust with black smoke pouring into the atmosphere
You night be put off by this catalytic converter price, but an inefficient part costs the environment more!


However, there is a way to keep your catalytic converter cost under control. When you book a ‘cat’ replacement or exhaust repair through BookMyGarage, you always get the best deal! Compare and save on thousands of UK fast fit, independent and franchise garages to get the best catalytic converter price in the UK. 



But is it worth paying such a high price for your catalytic converter replacement? We believe so! Here’s what your catalytic converter does to help you.


What is a Catalytic Converter?

CO2 (Carbon Dioxide) and NOx (Nitrogen Oxides) are gases made up of carbon, oxygen and nitrogen molecules bonded together through chemical reactions. These molecules are less harmful on their own, so modern exhaust systems are designed to release them into the atmosphere separately. 

The purpose of the catalytic converter is to split these molecules up before they can leave the exhaust.

The catalyst (the precious metal) speeds up the removal of pollution. It creates a chemical reaction with the exhaust gases, changing their structure. CO2, NOx and other harmful exhaust gases become oxygen and water vapour when filtered through the catalytic converter. These are much safer to release into the atmosphere.  

You can find a much more detailed explanation of how a catalytic converter works here.


car exhaust pipe housing catalytic converter on white background
Your catalytic converter sits within the exhaust manifold, breaking down harmful gases before they can be released into the atmosphere.


Does My Car Have to Have a Catalytic Converter?

Every car registered in the UK must have a ‘cat’ fitted by law. It became standard for petrol vehicles in 1992, and 2001 for diesels.

Petrol and diesel engines combust differently, so there are different types of cat converter.

‘Two-Way Oxidation’The first versions had a simple purpose. They turned Carbon Monoxide to CO2, and Hydrocarbons (particles of unburned fuel) to CO2 and water.

‘Three-Way-Oxidation’ – This type of catalytic converter is fitted to modern cars. It has the same purpose as ‘Two-Way Oxidation’ but reduces your NOx emissions as well. These include Nitric Oxide (NO) and Nitrogen Dioxide (NO2), which are the most harmful exhaust emissions.

‘Diesel Oxidation Catalyst’ – These units are fitted to diesel vehicles. Diesel cars naturally produce more pollution than petrol cars. Without any intervention, this would choke the planet. To combat the rising pollution levels, car companies invented several other exhaust treatments. These include Diesel Particulate Filters (DPF) and AdBlue.  

Of course, releasing CO2 into the atmosphere isn’t ideal, but our vehicles’ impact on the environment is greatly reduced thanks to your ‘cat’. More on this later.  


What Does it Look Like?

The ‘cat’ works best at 400 degrees Celsius. The first units were fitted near the engine but the excess heat caused more problems than it solved. You can now find your ‘cat’ at the back of your car.

To find your catalytic converter, you’ll need to kneel down behind your car and look at the exhaust assembly. Look for a large metal box with two pipes coming out of it, bolted to the bottom of your car. It looks like this.


zoomed in image of a catalytic converter on the underside of a vehicle
This is what you’re looking for when looking for your ‘cat’.


If you can’t see this box, you need to contact a local garage immediately. Don’t drive the car until you’ve had a professional exhaust inspection. Get your recovery provider to tow you to the garage for the appointment. If they agree that your exhaust is missing, contact the police. ‘Cat’ thefts are increasingly common in the UK because the catalyst materials are expensive precious metals. They are also easy targets because thieves can cut the entire exhaust manifold away from the car very quickly.  


Driving without a catalytic converter can cause serious problems, both to the environment and your engine. Here’s what to look out for.  


What Happens When the Catalytic Converter Goes Bad?

If there is a problem with your exhaust, you might see either of these warning lights.

Engine warning light and catalytic converter warning light
Your catalytic converter warning light is on the left, and your engine management light on the right.


If your warning light comes on at any point, you should get a reputable garage to complete an exhaust inspection or repair. You should always take a warning light seriously, but it’s even more important if you see the exhaust warning light. It could lead to an MOT failure and a seriously expensive repair bill if you don’t get the problem checked out.

Almost 1.3 million drivers failed an MOT due to excess exhaust emissions last year, many of which had problems with their catalytic converter.

And an MOT failure is the last thing you need.

However, if you book an exhaust repair through BookMyGarage, you can avoid this problem! If you notice either of the above engine warning lights, or any of the symptoms listed below, don’t waste time. Enter your reg number and post code into our online booking tool to compare and save on exhaust repair prices near you now!

If you notice any of these warning signs, it’s time to book an exhaust repair near you:

  • Engine runs rough.
  • Increased fuel consumption.
  • Increased emissions.
  • Excessive white smoke
  • Blue smoke
  • Slower acceleration times
  • The engine does not accelerate past a certain RPM (usually idle speed).
  • Your engine cuts out (due to additional backpressure).
  • There is a rattling noise from the exhaust

By catching the problem early, you can preserve your catalytic converter and avoid an MOT failure!  



How Long Should a Catalytic Converter Last?

Like most car parts, the lifespan of your ‘cat’ is affected by how you drive. Lots of stop-start journeys can wear it out quicker. Short journeys don’t bring the car up to the proper running temperature. This can increase your catalytic converter cost because you have to replace it more often.

However, if you look after your ‘cat’ properly, it should last between 70,000 and 100,000 miles.


How Long Does it Take to Replace a Catalytic Converter?

A catalytic converter replacement takes about 1-2 hours on average. It is quite easy to remove the assembly because of its location so the mechanic doesn’t have to disassemble your car. This saves you a lot of time!

For the best price on your ‘cat’ replacement, always choose BookMyGarage. You can compare and save on thousands of garages near you in just a few clicks. Filter by reviews, availability, distance or price to find the best deal on your next exhaust repair! Compare. Save. Job Done.  




We want to keep our cars as clean as possible and reduce our carbon footprint in whatever way we can. A catalytic converter plays a significant role in doing so. Here are the three main reasons to look after yours.

  1. An inefficient ‘cat’ increases your exhaust emissions. This can lead to an MOT failure and an expensive repair at an already stressful time.
  2. A replacement part can cost between £150 and £800, depending on the type of vehicle you drive. As a replacement is so expensive, you want to do everything you can to make it last around 100,000 miles, which is the maximum lifespan.
  3. You can suffer severe engine damage if the ‘cat’ becomes faulty. This can lead to a breakdown and a hefty engine repair bill. Book an exhaust repair or inspection instead to avoid these costs and receive peace of mind.

Mandy Weston

Mandy is an ex-mechanic, with 22 years’ experience in the motor industry. As an in-house motoring expert, Mandy is the go-to woman for any relevant questions that our customers have; both garages and drivers. From specific problems with your car to general maintenance, Mandy is a reliable source of information and advice. Her passion for motoring is a huge factor to her success and the huge wealth of knowledge that she has. She now uses her remarkable grasp of the industry to write regular content for our readers to help drivers understand their car better, avoid being ripped off by garages and save money on their motoring requirements.

7 Replies to “How Much Does a Catalytic Converter Cost? (2021)”

  1. Lili hunsaker says: Reply

    Thanks, great information!

  2. Cristina Sturzu says: Reply

    Hello! My question is this “if I buy a van with euro4 or euro5 can I change the catalytic convertor with euro6?
    Thank you!

    1. Mandy Weston says: Reply

      Hi Cristina,

      It is possible to make a diesel van meet the Euro 6 standard but I’m afraid it involves replacing more than just the catalytic convertor. If you just fitted a Euro 6 Cat to your vehicle you will likely find it will still not meet the 80mg/km limit. The limit for Euro 5 was 180mg/km, and Euro 4 was 250mg/km, this is a considerable drop in emissions to achieve.

      For Euro 5 to 6 you could consider a retrofit Selective Catalytic Reduction System (SCR)

      This includes:
      An SCR catalyst
      A Hydrolysis mixing section (A long piece of piping to promote removal of water from the AdBlue)
      AdBlue injectors (more than one may be required depending on the engine)
      A Control System (This controls the temperature pre and post catalyst and NOx output. This is how the adblue system works out volume to inject)

      For Euro 4 to 6 you would also need a diesel particulate filter.

      There are several companies that provide retrofit solutions to meet current Euro 6 standards but shop around as you could be looking in excess of £2500. Considering this extra expense, it’s probably more worthwhile spending a little more money and buying a van that already meets the Euro 6 standard.

      Hope this helps, and don’t hesitate to get back in touch if there’s anything else we can help you with.

  3. Sara Holland says: Reply

    My VW Golf (2008)has recently passed it’s MOT but I’ve been told the flexi pipe to the catalytic converter is leaking slightly. They have advised I get the cat changed at a cost of £1,600. Is this reasonable?
    Many thanks

    1. Mandy Weston says: Reply

      Hi Sara,

      If you just need a flexi-pipe replacement, these are quite inexpensive – you can find an aftermarket part for around £100 and ask a garage to just fit that.

      However, it could be that your catalytic converter is reaching the end of its life. Without knowing the condition of your ‘cat’ or the mileage of your car, £1,600 for a full replacement is a reasonable price. A catalytic converter has a lifespan of around 100,000 miles, so it may be that just replacing the flexi-pipe is not enough at this stage.

      Hope this helps 🙂

  4. Bridgette L Brown says: Reply

    Hey would you by any chance know how much a kia Sedona catalytic converter is worth

    1. Mandy Weston says: Reply

      Hi Bridgette,

      Aftermarket catalytic converters for your Kia Sedona don’t seem too expensive (between £70 and £200 from a motor factor) but it’s hard to be more specific without knowing your vehicle’s age and engine size. I would suggest that you contact some suppliers directly to get an accurate quote for your vehicle.

      Fortunately, the part doesn’t seem too expensive for you 🙂

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