If you were to measure your air filter, you are getting the actual size of the air filter. Actual Size is the true size of your air filter, but not necessarily the size listed online or on your air filter packaging. Here at Direct Filter Express, we are all about making your life simple. Calculate The Size Air Filter You Need.

Try Out Our Actual Size To Nominal Size Air Filter Converter to Calculate The Size Air Filter You Need

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actual size to nominal size air filter converter

What are nominal sizes?

Nominal size is the size you see printed on the side of your air filter. It stems from the actual size, which is rounded up to the nearest whole inch. There are hundreds of filter sizes and although manufacturers may make slight changes and offer very slight differences in their many filter sizes, the nominal size system ensures that you, the consumer, can fall back on industry standards and not have to have custom air filters made every time you need some clean air.

What are actual sizes?

The actual size is just what it says: the actual size of your air filter to a very precise degree. The actual size is accurate to one eighth of one inch. So for example:
A standard filter with a nominal size of 14″x14″x1″ might have an actual size of 13¾” x 13¾” x ¾”.
This actual size would be a pain to search for, which is why the nominal measurement was created.

So which one do I use?

The nominal size is the only one you really need to know when you look for air filters and it is typically printed on the cardboard edge of your air filter.

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