The Right Spark.
Every Single Time.
Honest spark plug reviews, fitment help and step-by-step install guides. We cover copper, platinum and iridium plugs for cars, trucks, motorcycles and small engines, so you buy the right plug the first time.
Plug Life at a Glance
Typical replacement interval by electrode material
Always follow the interval in your owner's manual. It overrides any general guide.
Browse the Garage
Find What You Need
Six sections that cover everything from picking a plug to fixing a stubborn misfire.
Spark Plug Reviews
Hands-on tests of NGK, Denso, Bosch, Champion, Autolite and more.
Read Reviews →Plugs by Vehicle
The right plug for popular Toyota, Ford, Honda, Chevy and Jeep engines.
Find Your Fit →Plug Types Explained
Copper vs platinum vs iridium, heat range and electrode design in plain words.
Learn the Basics →Install & Gapping
DIY replacement guides, torque specs and how to set the gap correctly.
Start a Guide →Ignition Troubleshooting
Misfires, fouled plugs, rough idle and reading old plugs like a mechanic.
Fix the Problem →Coils, Wires & Tools
Ignition coils, plug wires, sockets, gap tools and torque wrenches.
Shop Smarter →Quick Comparison
Copper vs Platinum vs Iridium
The electrode material decides how long a plug lasts and what it costs. Here is how the main types stack up.
| Plug Type | Typical Life | Price per Plug | Best For | Watch Out For |
|---|---|---|---|---|
| Copper | 20,000 to 30,000 mi | About $2 to $5 | Older engines, tuned and high-compression builds, small engines | Wears fast. Never use it to replace an OE iridium or platinum plug. |
| Platinum | Up to 60,000 mi | About $5 to $10 | Distributor ignition systems and many 1990s to 2000s cars | Single platinum is not ideal for waste-spark coil systems. |
| Double Platinum | 60,000 to 100,000 mi | About $8 to $15 | Waste-spark (coil-pack) ignition systems | Only use if your engine calls for it or allows it. |
| Iridium | 60,000 to 120,000 mi | About $8 to $20 | Most modern engines, coil-on-plug systems, turbo engines | Costs more up front. Do not re-gap with force, the fine tip breaks easily. |
Prices and intervals are general ranges. Your owner's manual and the plug maker's catalog are the final word.
Buyer's Checklist
Before You Buy: 5 Things That Matter
Most spark plug problems start with the wrong part, not a bad part. Check these five points and you will avoid nearly every return.
Full Buying GuideMatch the OE plug type
If your engine shipped with iridium, stay with iridium. Downgrading cuts plug life and can hurt performance.
Get the heat range right
Too hot and you risk pre-ignition. Too cold and the plug fouls. Stock engines need the stock heat range.
Check thread, reach and seat
Thread size, reach length and seat type (gasket or taper) must match your cylinder head exactly.
Verify the gap
"Pre-gapped" does not always mean gapped for your engine. Measure before you install.
Use a cross-reference chart
Switching brands? Confirm the part number with the maker's official cross-reference, not a seller listing.
Editor's Picks
Plugs We Would Put in Our Own Engines
Three standouts after testing for fit, idle quality, throttle response and wear.
[Placeholder: Iridium Plug Name]
Long service life, smooth idle and a fine-wire tip that fires cleanly in modern coil-on-plug engines.
- ✅ Up to 120k mile life
- ✅ Strong cold-start performance
- ⚠️ Higher price per plug
[Placeholder: Copper Plug Name]
Simple, cheap and reliable for older engines, lawn equipment and builds that call for copper.
- ✅ Lowest cost per set
- ✅ Great heat transfer
- ⚠️ Short replacement interval
[Placeholder: Performance Plug Name]
Colder heat range options for turbocharged, supercharged and tuned engines that run hot.
- ✅ Multiple heat ranges
- ✅ Built for boost
- ⚠️ Overkill for stock engines
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New reviews, fitment guides and fixes, published weekly.
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Is It Time to Change Your Plugs?
Enter your plug type and mileage. We will estimate how much life is left and when to plan the swap.
Fill in the form to see how much life your spark plugs have left.
Estimates only. Misfires, rough idle or poor fuel economy can mean plugs need attention sooner. Your owner's manual comes first.
FAQ
Spark Plug Questions, Answered
How often should I replace my spark plugs?
It depends on the plug material and your engine. Copper plugs often last 20,000 to 30,000 miles, while iridium plugs can last 60,000 to 120,000 miles. Your owner's manual lists the exact interval for your vehicle, so always start there.
Are iridium spark plugs worth the extra cost?
For most modern engines, yes. They last much longer, so you change them less often, and many engines are designed for them from the factory. If your engine originally used copper, iridium is usually fine but not always necessary.
Can I mix spark plug brands in one engine?
It is not recommended. Different brands can have slightly different firing behavior and wear rates. Install a full matched set of the same brand and part number for smooth, even running.
What are the signs of a bad spark plug?
Common signs include engine misfires, rough idle, hard starting, poor acceleration, a check engine light and lower fuel economy. A misfire code such as P0301 to P0308 often points to a specific cylinder.
Do I need to gap new spark plugs?
Always check the gap with a proper gauge before installing. Many plugs come pre-gapped, but the factory gap may not match your engine. Be gentle with fine-wire iridium and platinum tips, since they can break if forced.
Should I use anti-seize on spark plug threads?
Many plug makers say no, because their plugs have a protective plating and anti-seize can lead to over-tightening. Follow the plug maker's instructions and tighten to the specified torque.
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Why Trust BestSparkPlugs
Dale Whitaker
ASE Master Certified Automotive Technician
Dale has spent over 18 years in independent repair shops diagnosing ignition faults on everything from daily commuters to diesel-swapped trucks and weekend track cars. He installs, gaps and pulls every plug we review, then reads the wear like a mechanic would.
Meet the Team →Engine Misfiring or Not Sure Which Plug Fits?
Send us your year, make, model and engine. We will help you find the right plug or track down the problem.
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