Copper vs Iridium/Platinum Spark Plugs ( Pros and Cons)

spark plugs

Spare parts market is filled with all sorts of spark plugs nowadays. For last decade or so, platinum and iridium spark plugs have filled the market. These newer plugs are sold for as much as Rs1200 a piece (depending on type and brand). But the question is, are those run of the mill copper plugs thing of a past now? The following blog will try to answer that.

Also Read: Choosing the Right Spark Plug for the Best Performance

Life of spark plugs

In short, the answer is no. The main reason why parts manufacturers moved to materials like iridium or platinum is the longevity of the electrodes. A platinum or iridium spark plug will last you something like 80,000 to 100,000 kilometers. On the other hand, copper spark plugs will wear out at around 35,000 kilometers (give or take few thousand kilometers).

The trade-off

But the trade-off here is the conductivity of the spark plugs. Both platinum and iridium will last you long, but both of these metals are inferior conductors compared to something like copper. So in normal conditions, the copper spark plug will always outperform an iridium or some other fancy spark plug. But it will die in maybe less than half the age of these expensive plugs. People buy these spark plugs thinking they have improved the spark and hence increased the power of their stock vehicles but that is not true. One can debate whether iridium/platinum spark plugs improve the emissions/fuel economy but as far the performance is concerned, copper plugs are better in stock conditions.spark-plugs-cutBetween platinum and iridium plugs, iridium is considered a better option than the platinum, but it still doesn’t match copper’s conductivity.


The spark plugs like iridium or platinum are not just an aftermarket upgrade anymore. Cars like Honda Civic and Honda City now come with iridium spark plugs pre-installed. But as far as I know, Toyota Corolla still comes with regular copper plugs. To sum it all up, it is better to stick with what your car came installed with. Both types of plugs have their pros and cons. But it is always better and safer to use what your car manufacturer recommends.

Writing about cars and stuff.

Notable Replies

  1. Other than longevity, there is no other advantage of iridium/ platinum over regular spark plugs.
    It is hard for people to believe that if electrical system of a car is working alright then we'll not notice any difference in performance among the three types of spark plugs.

  2. Iridiums are long life spark plugs which work easily upto 100000km. Its better suited in cars where spark plug access is not easy. My corolla came factory fitted with Denso IK16 iridiums they easily lasted hundred thousand kms after that i put in regular copper nickel denso K16 and they worked nicely till 20000-25000kms. Iridium has 4 times more life compared to regular copper plug.

  3. You are right. According to my knowledge Spark Plug Life is belong how good your engine oil & your Fuel.

  4. nifiii says:

    How to know that your car now needs spark plug change?

  5. z06 says:

    Can you confirm which Plug is better for Corolla Altis 1.8 -- 2010 Model

    Also confirm the price and best location to get it done in Karachi.

    Thankyou :slight_smile:

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