The Spark Plug Cross-Reference Guide

A cross-reference finds the equivalent spark plug from a different brand. Done right, it matches the specs that matter — not the printed number. Here's how it works.

Why you can't just compare numbers

Each manufacturer has its own part-numbering system, and they don't align. Worse, some brands number heat range in opposite directions. So two plugs with similar-looking numbers can be completely different — and two very different-looking numbers can be exact equivalents.

What a real cross-reference matches

• Thread diameter — e.g. 14mm, 12mm, 10mm.
• Reach — how deep the plug threads into the head.
• Seat type — gasket (flat) or tapered.
• Heat range — normalized to a common scale so brands can be compared directly.
• Features — resistor, projected tip, electrode design.

How to use our tool

Enter a plug in the cross-reference tool and it returns every brand's true equivalent, each rated by how exact the match is. Or start from your vehicle and we'll give you the OE-correct plug plus its equivalents. To understand a number you already have, use the decoder.

A note on buying

Once you have the right plug (and its equivalents), you can buy whichever brand is cheapest or in stock. The tool links to Amazon, eBay and Advance Auto for each one.