12x30x1 air filter: actual size and MERV options
Last checked October 30, 2026
A 12x30x1 furnace or AC filter is a nominal 12 by 30 by 1 inch size. Nordic Pure publishes its actual size as 11.88 x 29.88 x 0.75 in.
Ratings sold in this size: MERV 6, MERV 7, MERV 8, MERV 10, MERV 11, MERV 12, MERV 13, MERV 14, MERV 16.
Fit is by size only. Read the size on your old filter frame or measure the slot before you order.
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Actual dimensions from filter makers
- 11.88 x 29.88 x 0.75 in, published by Nordic Pure for 12x30x1 Air Filter, MERV 13. Maker page, read October 30, 2026.
MERV options in 12x30x1
Similar sizes
Turn the system off at the thermostat before you change the filter. Arrows on the frame point toward the furnace, in the direction of airflow.
Questions
What is the actual size of a 12x30x1 filter?
Nordic Pure lists it as 11.88 x 29.88 x 0.75 in. Nominal sizes are rounded up, so the real filter is slightly smaller.
Will a 12x30x1 filter fit my furnace?
Yes if your filter slot takes a 12x30x1 filter. Fit is by size, not furnace model. Check the size printed on your old filter.
How often should I change it?
Follow your system manual and the filter maker. Many makers suggest checking a 1 inch filter monthly and replacing it about every 3 months; thicker filters last longer.