Spark Plug Cross Reference Chart 2026: Official Maker Lists

Short answer: A spark plug cross reference chart tells you which plug one manufacturer lists in place of another brand's plug. From the makers' own lists: a Champion RC12YC crosses to NGK BKR5E (NGK's guide) or DENSO K16R-U (DENSO's list); an NGK BKR5E-11 crosses to DENSO K16PR-U11; a Bosch FR7DC crosses to NGK BKR6E or FR5 or DENSO K20PR-U. Both makers call their lists a guide only, and in our check of 1,432 plugs that both makers cross, they pointed to the same DENSO plug only 46.3% of the time. Confirm the result with the application listing for your engine.

Every equivalent on this page comes from a plug maker's own published cross-reference, read on November 2, 2026: the DENSO Global cross-reference (its lists for NGK, Champion, Autolite, Bosch, ACDelco and Motorcraft plugs) and NGK Spark Plugs USA's automotive cross reference guide (2019 edition PDF) and non-automotive cross reference. For heat ranges and part-number letters we used DENSO's Identifying DENSO Plugs key and NGK's Spark Plug Basics page. We have not tested any plug. We did not build any equivalent ourselves by matching codes, and we did not chain one maker's list into another's. Each row says whose claim it is.

Spark Plug Cross Reference Chart: Common Plugs at a Glance

This is the quick version for the plugs people search for most. Each answer is the maker's own pick for that plug.

Sources: NGK automotive cross reference (2019 edition); DENSO Global cross-reference lists. Read November 2, 2026. Full tables, with DENSO iridium options, are below.

Two things are already visible. First, NGK often lists more than one plug for a single competitor number, and those plugs are not the same as each other. Second, the two makers do not always agree. For the RC12YC, NGK says BKR5E. DENSO says K16R-U. But DENSO's own entry for an NGK BKR5E is K16PR-U, not K16R-U. In DENSO's code key, the P marks a projected insulator (1.5 mm projection). So the two makers disagree about whether the RC12YC's equivalent should be the projected-tip plug or not. Neither list is wrong on its own terms. Each is one company's view of its own range.

What a Cross Reference Can and Cannot Tell You

A cross reference answers one narrow question: "if I hand you this plug, which of yours do you list for it?" It does not say the two plugs are identical, and it does not say either plug is right for your engine. Both makers say so in plain language. NGK prints the same note on every page of its guide: "Cross references are provided as a GUIDE ONLY. Due to differences in design / materials, products produced by various mfrs may have different specifications. Please refer to specific application guide for proper usage." DENSO's cross-reference caution says the chart "does not guarantee adaptability to vehicles," that plug specifications vary by manufacturer, and that you should choose your plug by referring to its vehicle compatibility table.

That matters because of who is making the claim. When NGK lists an NGK plug for a Champion number, NGK is the one standing behind that pick, and the same goes for DENSO. That is a stronger claim than a third-party table saying one brand equals another, a difference we explain in our guide to how to read a spark plug part number. The same idea applies well beyond plugs, as our article on what to check in an oil filter cross-reference shows. But even a maker's own cross is a match to its own catalog, not a measurement of your engine.

Champion Spark Plug Cross Reference Chart

Champion numbers are among the most common on older cars, small engines and replacement plugs. These are what NGK and DENSO each list for common Champion copper plugs.

NGK column: NGK Spark Plugs USA automotive cross reference (2019 edition PDF). DENSO columns: DENSO Global cross-reference list for that brand. Both read November 2, 2026. A dash means that maker lists no equivalent. Where NGK lists several plugs, all are shown in NGK's order.

Look at the RN14YC row. NGK lists three plugs (GR4, BPR4ES and BPR5ES) where DENSO lists one, W16EPR-U. Look at the RN12YC and RN14YC together, too: NGK lists BPR5ES for both, while DENSO separates them into W16EXR-U and W16EPR-U. In DENSO's key, X means a fully projected insulator (2.5 mm projection) and P means a projected one (1.5 mm). The same competitor plug can lead you to different tip designs depending on whose list you read.

Champion small engine plugs

Mowers, trimmers and other small engines often carry Champion J-series and RCJ-series plugs. NGK covers these in its separate non-automotive guide. If your engine is a Briggs & Stratton, start with Briggs' own list in our Briggs and Stratton spark plug chart, which shows which Briggs part replaces a Champion RC12YC and an RJ19LMC.

Sources: NGK Spark Plugs USA non-automotive cross reference (2019 edition PDF), Champion to NGK pages; DENSO Global Champion list. Both read November 2, 2026. DENSO lists no iridium equivalent for these three.

Autolite Spark Plug Cross Reference Chart

Autolite numbers are all digits, which makes them easy to mistype and impossible to read by eye. These are the NGK and DENSO picks for common Autolite copper plugs.

NGK column: NGK Spark Plugs USA automotive cross reference (2019 edition PDF). DENSO columns: DENSO Global cross-reference list for that brand. Both read November 2, 2026. A dash means that maker lists no equivalent. Where NGK lists several plugs, all are shown in NGK's order.

The Autolite rows show the widest spread of answers. NGK lists four plugs for a 3924: BKR6ES-11, BKR5E-11, FR5 and BKR5E. Follow DENSO's own crosses for those four NGK plugs and they land on two different DENSO heat ranges: BKR5E-11 and BKR5E go to 16 (K16PR-U11 and K16PR-U), while BKR6ES-11 and FR5 go to 20 (K20PR-U11 and K20PR-U). DENSO's own answer for the 3924 is a third type, PQ16R, a platinum plug in DENSO's coding. That one row shows why "the equivalent" can be several different plugs.

The 63 and 64 rows show the opposite problem. NGK lists BPR6ES for both (and GR5 and BPR5ES-11 as further options for the 64). DENSO lists W22EPR-U for the 63 and W20EXR-U for the 64: a different heat range number (22 against 20) and a different projection letter (P against X). Autolite is also missing from DENSO's heat range table, so there is no official shortcut for comparing an Autolite plug's heat range with the others.

Bosch Spark Plug Cross Reference Chart

Bosch's copper plugs use letter-and-number codes such as FR7DC and WR7DC. Here are the NGK and DENSO picks.

NGK column: NGK Spark Plugs USA automotive cross reference (2019 edition PDF). DENSO columns: DENSO Global cross-reference list for that brand. Both read November 2, 2026. A dash means that maker lists no equivalent. Where NGK lists several plugs, all are shown in NGK's order.

This is where the two lists agree most closely on the popular plugs. For the FR7DC, NGK's BKR6E and DENSO's K20PR-U line up, because DENSO lists K20PR-U for an NGK BKR6E as well. The same holds for the FR8DC (NGK BKR5E, DENSO K16PR-U) and for their X versions, FR7DCX and FR8DCX, which pick up the -11 NGK plugs and the -U11 DENSO plugs. In DENSO's key, 11 in that position means a 1.1 mm (.044 in) gap.

NGK to DENSO Cross Reference Chart

If you already have an NGK number and want the DENSO version, DENSO publishes that list directly. These are its picks for common NGK plugs, with the iridium alternatives DENSO names alongside the standard plug.

Source: DENSO Global cross-reference, NGK (Japan) list, read November 2, 2026. DENSO writes NGK numbers without hyphens (BKR5E11); we show NGK's usual form. NGK ZFR5F-11 and ZFR6F-11 are not on DENSO's list, so they are left out.

For the most common pairs, NGK's guide confirms the match in the other direction. NGK lists BKR5E-11 for a DENSO K16PR-U11, BKR6E-11 for a K20PR-U11, and BKR6E for a K20PR-U. When both makers point at each other like this, you can be more confident the two plugs are meant to do the same job. The BPR6ES is a useful warning, though: DENSO lists W20EXR-U for it, while NGK's guide lists BPR6EY for a W20EXR-U. A match in one direction does not guarantee the same match coming back.

How Often NGK and DENSO Agree

The examples above raised a fair question: how often do the two makers' answers agree? We checked every case we could. For each Champion, Autolite, Bosch, ACDelco and Motorcraft plug that appears in both DENSO's lists and NGK's automotive guide, we took DENSO's pick. Then we took NGK's pick (or picks) and looked up the DENSO plug that DENSO lists for each of those NGK plugs. If that matched DENSO's direct answer, the two makers agree. We left out 89 plugs where DENSO lists no DENSO plug for any of NGK's picks, which left 1,432 plugs to compare.

Our analysis of the NGK automotive cross reference (2019 edition) and the DENSO Global cross-reference lists (read November 2, 2026). Method in the text.

Across all five brands, the two makers agreed on 663 of 1,432 plugs (46.3%). Another 263 (18.4%) differed only in the heat range number of the DENSO code, such as K16PR-U against K20PR-U. The remaining 506 (35.3%) differed somewhere else in the code: projection, resistor, electrode metal or plug family. We counted a match if any one of NGK's options matched, which flatters the agreement rate rather than lowering it.

Three limits matter. The NGK guide is a 2019 edition and DENSO's lists are current, so some differences may come from updates on either side. We read the NGK PDF with software and checked samples against the printed pages, but a few rows could still be misread. And agreement does not prove fitment: two makers can both be wrong for a modified engine. The takeaway is simple. A cross reference narrows the field. The application listing for your engine settles it.

Spark Plug Heat Range Across Brands

Heat range is the part of a cross that matters most for engine safety. NGK's heat range guide says it "only indicates the rate that the spark plug dissipates its firing end heat to the engine," and has nothing to do with spark intensity. A plug that runs too cold can foul. One that runs too hot can overheat and cause pre-ignition, which NGK's basics page warns "can cause serious and expensive engine damage." DENSO's heat range page puts the working window at a center electrode temperature between about 500°C and 950°C.

The brands do not number heat range the same way. NGK says "lower numbers indicate a hotter type, higher numbers indicate a colder type." DENSO's conversion table lines its numbers up with NGK's in the same direction, so higher DENSO numbers are colder too. Champion and Bosch numbers mostly fall as the plug gets colder, as the same table shows.

Source: DENSO, "Identifying DENSO Plugs" heat range table (excerpt), read November 2, 2026. Read across a row. Hotter plugs are at the top. DENSO's table has no Autolite column.

Use this table to sanity-check a cross, not to make one. If a cross takes you from a Champion 12 to an NGK 6, for example, DENSO's table says that is one step colder than the NGK 5 that sits beside a Champion 12. NGK also notes that for most vehicles the factory recommended heat range is enough, and that fitting a hotter plug reduces the pre-ignition safety margin. Our spark plug heat range chart has DENSO's full table and each maker's own scale.

How to Read the Plug Codes in This Chart

You do not need to decode every letter to use a cross reference, but knowing a few helps you spot a bad match. DENSO publishes its full key. Take K16PR-U11, the DENSO plug for an NGK BKR5E-11:

• K: 14 mm thread, 16 mm hex (DENSO calls this a miniature plug).
• 16: heat range.
• P: projected insulator, 1.5 mm projection.
• R: 5 kohm resistor.
• -U: U-groove ground electrode.
• 11: 1.1 mm (.044 in) gap.

Other makers use different letters for the same features, so a K in a DENSO code tells you nothing about a K in another brand's code. The part-number guide linked above covers the five properties that must match whatever the brand: thread, reach, seat, heat range and the resistor and electrode details.

How to Use a Spark Plug Cross Reference Safely

1. Start from the engine, not the old plug. If you can, look up your vehicle or engine in the plug maker's application listing. The plug that came out may not be the right one. Our guide to finding your engine code helps when the model name alone is not enough.
2. If you only have the old plug, read its number carefully. Autolite numbers are all digits and easy to swap. Copy the number exactly, including any suffix.
3. Cross it in the maker's own list. Use the target brand's cross-reference (NGK's guide for an NGK plug, DENSO's lists for a DENSO plug), not a reseller's table.
4. If several plugs are listed, do not pick at random. Check each against the application listing for your engine.
5. Check the reverse direction. If the other maker crosses back to your original plug, that is a good sign. If not, find out why.
6. Check the heat range step. Use DENSO's table above to confirm the new plug is not a step hotter or colder than the old one, unless the application listing calls for that.
7. Check and set the gap for your engine. The gap your engine needs comes from the engine maker. Our guide on where to find the spark plug gap spec explains where to find it.
8. Install to the plug maker's instructions. Thread by hand first and tighten to the specified torque. Cross-threading and over-tightening are the two classic ways to damage a cylinder head.

Common Mistakes With Spark Plug Cross Reference Charts

• Treating "equivalent" as "identical." Both NGK and DENSO say their crosses are for reference only.
• Chaining crosses. Going from Champion to NGK in one list, then NGK to DENSO in another, can land you on a different plug than DENSO's direct cross. For the RC12YC, the chained route gives K16PR-U while DENSO's direct answer is K16R-U.
• Carrying a heat range number across brands. In DENSO's table an NGK 9 sits on the cold side, beside a Champion 4 or 59, while a Champion 9 sits beside an NGK 6.
• Trusting undated printed charts. Some multi-brand interchange charts that circulate online carry no date and no clear publisher. Use the plug maker's own list.
• Ignoring the gap. A cross matches the plug type, not your engine's gap.
• Using a cross reference on a modified engine. DENSO says that for tuned or modified vehicles, choosing a plug is at your own discretion and responsibility.

Frequently Asked Questions

What is the NGK equivalent of a Champion RC12YC?

NGK's automotive cross reference lists BKR5E. DENSO's own list gives K16R-U for the RC12YC, with IK16 (Iridium Power) and VK16 (Iridium Tough) as iridium options. For Briggs & Stratton OHV engines, Briggs lists its own 491055S as the RC12YC replacement.

What is the DENSO equivalent of an NGK BKR5E-11?

DENSO's cross-reference lists K16PR-U11, with IK16 and VK16 as its iridium options. NGK's guide agrees in the other direction: it lists BKR5E-11 for a DENSO K16PR-U11.

Is a spark plug cross reference chart reliable?

It is a starting point, not a fitment guarantee. NGK says its cross references are "provided as a GUIDE ONLY," and DENSO says its chart "does not guarantee adaptability to vehicles." In our comparison of the two makers' lists, they pointed to the same DENSO plug for only 46.3% of the competitor plugs both of them cross.

Why do NGK and DENSO list different equivalents for the same plug?

Each maker matches a competitor plug to its own range, and the ranges are not built the same way. NGK says plug designs and materials differ between manufacturers, and DENSO says plug specifications vary by manufacturer. In our comparison, 18.4% of differences were only a heat range step apart and 35.3% differed in other parts of the code.

Can I use a heat range number to cross brands?

Not directly. NGK says lower NGK numbers are hotter and higher numbers are colder. DENSO's heat range table lines up its numbers with NGK, Champion and Bosch (DENSO 20 sits beside NGK 6, Champion 10 or 9, and Bosch 7 or 6), and Champion and Bosch numbers mostly run the other way. Autolite does not appear in DENSO's table.

Why does NGK list more than one plug for the same competitor number?

NGK's guide often lists several NGK plugs for one competitor plug, such as four for an Autolite 3924. They are not identical to each other. DENSO's own crosses for those four NGK plugs land on two different DENSO heat ranges, 16 and 20, so check the application listing for your engine before choosing.

Should I use a cross reference or a vehicle lookup?

Use the vehicle or engine application listing first. DENSO tells you to choose your plug by referring to its vehicle compatibility table, and NGK tells you to refer to the specific application guide. Use the cross reference when you only have the old plug in your hand, then confirm the result against the application listing.

Do I need to change the gap when I cross to another brand?

Check it. A different plug can come with a different factory gap, and the gap your engine needs is set by the engine maker, not by the plug's part number. Look up the gap for your engine and set it the way the plug maker's instructions allow.

Sources

• DENSO Global, Cross Reference: Search by spark plug manufacturer, including the NGK, Champion, Autolite and Bosch lists and the ACDelco and Motorcraft lists, read November 2, 2026.
• DENSO Global, Cross Reference (caution notes), read November 2, 2026.
• DENSO Global, Identifying DENSO Plugs (part number key and heat range table), read November 2, 2026.
• DENSO Global, Heat Range (basic knowledge), read November 2, 2026.
• NGK Spark Plugs USA, Spark Plug Cross Reference, automotive (2019 edition PDF), read November 2, 2026.
• NGK Spark Plugs USA, Spark Plug Cross Reference, non-automotive (2019 edition PDF), read November 2, 2026.
• NGK Spark Plugs USA, Spark Plug Basics (updated May 17, 2019), read November 2, 2026.
• NGK Spark Plugs USA, Understanding Spark Plug Heat Range (updated April 30, 2025), read November 2, 2026.