Catalytic Converter Replacement Cost Calculator

Under the Clean Air Act, every US vehicle carries a federal emissions warranty. It covers the catalytic converter for 8 years or 80,000 miles.

If your car qualifies and the converter failed from normal use, the dealer must replace it free. Physical damage and contamination void the warranty claim.

California extends this to 15 years or 150,000 miles for major emissions components under CARB rules.

Check your odometer and purchase date before approving any quote. If you qualify, go to a dealer with your maintenance records and request warranty coverage. If the dealer refuses a legitimate claim, file a complaint at nhtsa.gov. That enforcement mechanism exists for exactly this situation.

The shop can't tell you whether the part they're installing is OEM or aftermarket by brand name. A reputable shop knows exactly what's going on the car and can show you the box.

They quoted a "universal fit" converter in a CARB state. Universal converters require welding modifications, fail smog at higher rates, and are not CARB-compliant. Insist on direct-fit with a visible EO number.

No written estimate before starting work. Verbal quotes are unenforceable. Get the full breakdown on paper, including whether O2 sensors and gaskets are included.

Pressure to approve the repair today without explaining what caused the converter to fail. If they haven't diagnosed the root cause, you could be paying for a part that fails again in 10,000 miles. Ask: "What caused this converter to fail?"

They want to dispose of your old converter without offering it to you. Failed converters still contain scrap-value precious metals ($15–$150). A shop that pockets the old part without asking is cutting you out of value that's yours.

A typical independent shop invoice for a 2015 Accord with P0420 runs about $495–$645. That covers an aftermarket CARB converter at $250–$400 (typical 2026 retail), two hours of labor at $100/hr, gaskets at $25, and one O2 sensor at $120.

The same job at a dealer uses an OEM converter at $600–$1,200, bills 2 hours at $160/hr, and adds the same sensor, landing at $1,040–$1,720. The part drives the gap, not the wrench time.

California residents face both CARB part requirements and higher labor rates. BEA Regional Price Parities data shows metro areas like San Francisco carry a 15–20% premium on service costs over the national average.

Select your vehicle class in the calculator above and compare. An economy car in a non-CARB state can land under $500 at an independent shop.

Palladium and rhodium are what make a catalytic converter work. The hybrid drivetrain in a Prius runs at lower temperatures than a conventional engine. The converter needs more precious metal loading to catalyze exhaust reactions at those temps.

More precious metal per converter means a higher part price and a bigger payday for thieves. That's why Prius owners see OEM replacement quotes of $1,800–$2,600 while a Honda Accord OEM converter runs $600–$1,200.

CARB-compliant aftermarket options bring the Prius part down to $800–$1,200, but availability is limited. Not every aftermarket part passes the Toyota OBD monitor on the first drive cycle.

Prius owners weighing full hybrid ownership costs should check the hybrid battery replacement cost calculator for the other big-ticket item ahead.

If you own a Prius, Tacoma, or Honda Element, budget for a catalytic converter anti-theft shield after replacement. Details are in the anti-theft section below.

Seventeen states and Washington, D.C., follow California Air Resources Board emissions standards instead of federal EPA specs. Install a federal-spec aftermarket converter in one of these states and it fails smog immediately. The part is non-returnable once installed, so the mistake means buying a second converter.

CARB states as of 2026: CA, OR, WA, CO, MN, NY, ME, MA, CT, RI, VT, NJ, PA, MD, DC, DE, NV, and NM.

Every CARB-compliant aftermarket converter carries a California Executive Order (EO) number stamped on the housing. Ask the shop before installation: "Can I see the EO number on the box?" If they can't produce one, the part is federal-spec, not CARB.

CARB-spec converters run $100–$400 more than the equivalent federal part. The calculator above adjusts for this automatically when you select a CARB state. Verify the EO number yourself at the CARB database on arb.ca.gov before approving the work.

A new converter installed on an engine that's burning oil, misfiring, or leaking coolant will fail again within 10,000–30,000 miles. The contaminants that killed the first one destroy the replacement just as fast.

Before approving converter replacement, ask: "What caused this one to fail, and is that root cause fixed?" The answer determines your repair strategy.

P0420 code only, no misfire codes, no oil consumption: the converter wore out from age. Safe to replace.

P0420 plus misfire codes (P0300–P0312): fix the misfire source first. Worn spark plugs are the most common culprit at $200–$400. Skipping this step adds $800–$3,000 for a second converter within two years.

Physical damage from road debris or theft: no root cause issue, replace and move on. If the shop says your engine has an oil leak that caused the failure, get the engine repair quoted separately before committing to the converter.

P0420 efficiency code, engine runs normally: you have 500–2,000 miles. Fuel economy drops 3–8%, but no mechanical damage is happening. Schedule the repair at your convenience and use the time to get a second quote.

Physically clogged converter with power loss or heat smell: drive as little as possible. A fully blocked converter causes engine-damaging backpressure and can stall the car at highway speed. Get this done within one to two weeks.

Rattling from inside the converter housing: stop driving. The ceramic monolith has broken apart, and fragments can enter the engine through the exhaust valves. This turns a $900 converter job into a $5,000–$12,000 engine rebuild. Tow it to the shop.

Stolen converter: do not drive. Open exhaust dumps raw fumes into the cabin and the noise alone can cause hearing damage on a highway. Call your insurer, file a police report, and arrange a tow.

Federal aftermarket converters are fine for most drivers in non-CARB states. Brands like Walker, Bosal, and Magnaflow (non-CARB spec) start at $80 for economy cars at typical retail.

OEM is mandatory in three situations. Your vehicle is under powertrain warranty. You drive a BMW, Mercedes, or Audi where aftermarket parts rarely pass proprietary OBD monitors. Or a Honda/Toyota TSB specifies OEM-only for your P0420 fix.

Never accept a "universal fit" converter. These require welding, often don't seat correctly, and fail smog at higher rates than direct-fit parts. Ask for a direct-fit (bolt-on) part by name when you call for a quote.

The shop's actual cost to put one technician on your car for two hours is roughly $67–$90. They bill $85–$135/hr at an independent shop, $120–$180/hr at a chain (Midas, Meineke, Firestone), or $130–$200/hr at a dealer. The difference covers rent, diagnostic equipment, insurance, and margin.

Chain shops sit between independent and dealer on labor rate but structure quotes differently. They often bundle diagnostics into the converter job and stock a mix of OEM and aftermarket parts depending on the vehicle. Get the part brand in writing before approving work.

Knowing this changes how you read a quote. A $200 labor charge at an independent shop for 2 hours ($100/hr) is reasonable, not a ripoff. A $400 labor charge at a dealer for the same 2 hours ($200/hr) includes real overhead, not just a luxury markup.

When the bill says 3.5 hours on a job that normally takes 2, ask what added the time. Corroded bolts in rust-belt states are a legitimate reason. Vague explanations are not.

Three factors stack against high-cost state residents. CARB-spec parts run $100–$400 more than federal equivalents, and shop labor rates hit $130–$200/hr in San Francisco versus $75–$100/hr in Houston.

Theft-driven demand in cities like Seattle and the Bay Area creates 2–4 week backlogs for popular models. That wait adds rental car costs on top of the repair bill.

Rough ranges for a single aftermarket converter on a mid-size car. Southeast non-CARB $350–$800. Midwest non-CARB $400–$950 (add $80–$200 for rust labor).

Northeast CARB states $600–$1,400. West Coast CARB $650–$1,600. California $750–$2,200.

The calculator factors in your state's labor rates and CARB requirements automatically. If your result seems high compared to a national average you saw elsewhere, the CARB part premium and your local shop rate are the reason.

Step 1: File a police report the same day. Some states impose a 24-hour window, and every insurer requires the report number before processing a claim. Do not skip this even if you plan to pay out of pocket.

Step 2: Call your auto insurer before authorizing any repair work. Catalytic converter theft falls under your comp coverage, not collision. Some insurers require pre-authorization or a specific shop. Authorizing work before the call can void your claim.

Step 3: Run the deductible math. If your deductible is $500 and the repair quote is $800, you net $300 from the claim. A comp claim raises your premium $50–$200/yr for three years, totaling $150–$600 in increased premiums. Paying $800 out of pocket often costs less over three years than filing.

Step 4: Choose a shop, authorize the repair, and request an anti-theft shield installed at the same time. On a Prius, Tacoma, or Honda Element, the shield is not optional. It's $200–$500 now versus $2,000–$3,000 for the next theft.

A brand-new converter will still fail a smog inspection if you drive straight to the testing station. The OBD catalyst monitor needs 50–200 miles of mixed city and highway driving to complete its readiness cycle. Without that cycle, the test reports "incomplete monitors" and you fail.

Drive normally for 100–200 miles, mixing freeway cruising with stop-and-go. Then check your OBD readiness status with a $20 scan tool or ask any auto parts store to read it free. All monitors should show "ready" before you book the smog appointment.

If the catalyst monitor still shows "not ready" after 300 miles, the root cause of the original failure may not be fully resolved. Go back to the shop. Have them check for pending codes or a bad O2 sensor before you pay for another test.

An unprotected Prius converter can be cut off in 60–90 seconds. A catalytic converter shield extends that to 5–15 minutes, which is enough to make most thieves move to an easier target.

1. Confirm vehicle model compatibility — shields are year- and trim-specific.
2. Choose plate vs. cable style based on installer recommendation and your parking situation.
3. Schedule installation on the same day as converter replacement so the car is already on the lift.
4. Photograph the installed shield and email the photo to your insurance agent for documentation.

Three brands dominate the market: MillerCAT ($250–$400 installed), Prius Shield ($200–$350 installed), and CatStrap ($150–$300 installed, cable-style). All are vehicle-specific and bolt on without welding.

The ROI is straightforward. One shield installation at $300 versus one repeat theft and replacement at $2,000–$3,000. Some insurers offer premium discounts for documented anti-theft devices, which shortens the payback further.

If you own a Prius, Tacoma, Honda Element, or Ford F-250 diesel, install the shield the same day as the converter replacement. Having the car already on the lift makes installation faster and cheaper.