Iridium spark plugs are typically the most expensive type among mainstream spark plugs, with ultra-premium racing designs sometimes costing even more. The price reflects the materials, precision manufacturing, and longevity benefits they offer.
Types of spark plugs and price bands
The following list outlines the main categories you’ll find on store shelves or in OEM specifications, ordered roughly by common price points. This helps explain why some plugs cost more than others.
- Copper-core spark plugs
- Platinum spark plugs
- Iridium spark plugs
- Double-platinum or platinum–iridium spark plugs
- Specialty high-performance racing plugs
Prices vary by brand, heat range, and engineering features, but the general ranking from least to most expensive usually follows copper-core, platinum, iridium, platinum-iridium variants, and then specialty racing designs.
Iridium: the premium tier
Iridium-based plugs sit at the premium end of the market due to their material properties and precision manufacturing. They use an iridium alloy for one or both electrodes, enabling a thinner center electrode, longer life, and stable performance across a wide range of temperatures. This combination drives up the price relative to copper or plain platinum plugs.
Material and manufacturing
Iridium is a relatively rare, hard metal. The electrodes are engineered to be thinner and more durable, reducing wear and extending service intervals. The manufacturing processes—such as precision welding and tight tolerances—contribute to higher production costs, which shoppers see reflected in the price per plug.
In vehicles today
Many modern engines—from everyday hatchbacks to some light-duty pickups—use iridium or platinum–iridium plugs for improved longevity and cleaner combustion. While these plugs cost more upfront, their longer life can reduce maintenance frequency and improve reliability over time.
Price ranges for common spark plug types
Prices shown are approximate retail ranges for individual plugs in North American markets as of 2024–2026. Actual prices vary by brand, model, and region.
- Copper-core plugs: typically about $0.50 to $2 per plug for standard lines; premium copper cores may be slightly higher.
- Platinum plugs: roughly $3 to $8 per plug, with premium platinum lines edging higher.
- Iridium plugs: commonly $6 to $15 per plug; some premium or specialized lines run higher.
- Double-platinum or platinum–iridium plugs: about $8 to $16 per plug, with premium variants higher still.
- Specialty racing plugs: generally $20 to $60+ per plug, depending on design, materials, and customization.
These ranges illustrate the general price hierarchy: copper-core < platinum < iridium < platinum-iridium/double-platinum, with racing and specialized designs often at the high end. Brand, heat range, and performance features can shift prices within these bands.
Ultra-premium and racing plugs
For professional racing or highly specialized engines, manufacturers offer ultra-premium plugs built with advanced materials—such as laser-welded iridium electrodes, exotic alloy compositions, or unique electrode geometries. These can command substantially higher prices per plug and are typically selected for specific competition rules or extreme endurance demands.
What makes them expensive
The cost drivers include bespoke manufacturing, limited production runs, and materials designed for maximum endurance under extreme conditions. These plugs may also be tailored to very specific engine configurations, further driving up price and often requiring dealer or team-level support.
Summary
In standard consumer and OEM contexts, iridium-based spark plugs are the most expensive type, thanks to durable iridium electrodes and precision manufacturing that deliver longer life and steadier performance. As a rule, you’ll pay more upfront for iridium than for copper-core or simple platinum plugs, and racing or specialty models can push prices even higher. For many drivers, the choice comes down to the recommended heat range and service intervals for their engine—cost versus longevity and performance.
Which spark plug is better, iridium or copper?
This means iridium spark plugs have a longer lifespan, often lasting up to 100,000 miles. But that's not all. Iridium spark plugs have a fine wire center electrode that requires less voltage to create a spark. This results in a more efficient combustion process, better fuel economy, and a smoother idle.
What's better, NGK platinum or iridium?
Iridium is said to be six times harder and eight times stronger than platinum with a 700° higher melting point. Iridium spark plugs have extremely fine electrodes while retaining excellent wear characteristics. Thanks to its strength, iridium spark plugs can last up to 25% longer than comparable platinum spark plugs.
Are iridium spark plugs more expensive than platinum?
At around $4 to $8 each for most vehicles, platinum spark plugs are only a small jump in price compared to copper. Iridium spark plugs cost approximately double, on average, with most options between $8 and $15 each.
Is ruthenium better than iridium?
Iridium spark plugs are typically less expensive than ruthenium, but the difference is modest. Ruthenium plugs come at a premium but may offer a longer service life and better performance under stress.