WE ARE OPEN! All filters are made in the USA in our Alabama warehouse.

Custom Air Filters

Custom AC or furnace filter

Custom size air filters are built to your exact specifications. As a result, these filters may not be returned for refund or credit. All custom size air filters are built to tolerances of + or - 1/8". Custom air filters lead time may take longer than the standard size filters. In most cases, orders are shipped within 2 weeks or sooner.

Most air filters are stamped with a size that is NOT the actual dimension of the filter. Example: A 20x20x1 filter typically measures 19 3/4 x 19 3/4 x 3/4. Please measure your current air filter in order to get the exact dimensions.

Filter King does carry over 300 standard sizes. Please check our Air Filter Size Page. (Standard size filters are much cheaper and ship within 24 hours)

Filter King Thickness Specifications

Stated Thickness:
Actual Thickness:

Filter King can make pretty much any size filter! For price quotes on sizes not available online or if you have other questions or want a bulk discount, call Filter King Call 877-570-9755.