Spark Plug Replacement Cost: Parts, Labor & Average Price

Spark plugs ignite the fuel and air mixture in each cylinder. Worn plugs can cause rough idling, poor fuel economy, hard starts, and misfires. The job is routine maintenance, but the total depends on how many cylinders the engine has, what type of plug it uses, and how hard the plugs are to reach.

Prices come from AAA and a second published estimate, with a check date of Oct 11, 2026. The tables below split the total into engine size, plug type, and labor.

Engine size matters because every cylinder needs its own plug. A V8 has twice as many plugs as a four-cylinder engine, and on many V6 and V8 engines some of them sit under the intake manifold or behind other parts.

The range within each row depends on the plug type and how much of the engine has to be moved to reach the plugs.

The plugs themselves are inexpensive. The table shows the price of a single plug by material. Multiply by the number of cylinders to estimate the parts cost.

Copper plugs cost the least and wear out the fastest. Platinum and iridium plugs cost more per plug and are built to last longer. Use the type your vehicle's manufacturer specifies. Fitting a different plug than the manual calls for can affect how the engine runs, and some engines are sensitive to plug type.

Shop labor is the other half of the bill. The table shows a published range of hourly rates.

Plugs on an easy to reach four-cylinder can be changed quickly, so labor stays low. If the shop has to remove a plastic engine cover, ignition coils, or an intake manifold to reach the plugs, the job takes longer and costs more. Hourly rates are usually higher at dealerships and in large metro areas.

• Number of cylinders. More cylinders mean more plugs and, usually, more labor.
• Plug material. Copper, platinum, and iridium differ in price per plug.
• Engine layout. Transverse V6 engines and some turbocharged engines can be difficult to reach.
• Related parts. Shops sometimes recommend new ignition coils or plug wires at the same time if they are worn or cracked.
• Shop type. Dealership, chain, and independent shop rates differ.
• Vehicle age. An older plug may be seized or corroded in the cylinder head, which adds time.

Published numbers can differ because they measure different things. A range from an auto club may cover many engine sizes, while a figure from an app that collects repair data may reflect the typical vehicle on its platform.

The second source above lists a narrow range, which suggests a common four-cylinder job. The first covers a wider set of engines. Compare against the row that matches your engine and then ask your shop for an itemized quote.

Replacement intervals depend on the plug type and the vehicle, so your owner's manual is the best guide. Many modern vehicles with long life plugs go many miles between changes, while older vehicles with copper plugs need them more often. Warning signs include rough idle, hesitation when accelerating, hard starting, a drop in fuel economy, and a check engine light with a misfire code.

Waiting too long can let a worn plug damage an ignition coil or foul the catalytic converter through repeated misfires, which makes the eventual repair more expensive.

Changing spark plugs is a common DIY job on engines where the plugs are easy to reach. You need a spark plug socket, a torque wrench, and a gap tool for plugs that are not pre-gapped. Over tightening can damage the cylinder head threads, and under tightening can let the plug work loose. Cross threading a plug in an aluminum head is an expensive mistake. If your engine buries the plugs under other components, a shop is often the safer choice.

• Which plug type and brand is quoted, and does it match the manual?
• Is the price for all cylinders, with labor included?
• Will ignition coils or wires be inspected or replaced?
• Is there a diagnostic fee if the car has a misfire?
• What warranty covers the parts and the work?