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Custom Made Air Filters

Create your custom AC or furnace filter in just a few clicks


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.

Custom Made Air Filters or AC & Furnace Filters

Custom air filters tailored to your exact AC & furnace specifications. Need an odd size? No worries! Top MERV ratings available. Made in the USA. Fast shipping!

Custom AC or Furnace Filter: Build Your Own

If you find that our standard size filters do not fit your home, consider a custom size air filter built for your specifications. We make them with tolerances of ± ⅛”. Even though they take longer to manufacture than our standardized filters, you will still receive them within two weeks. Filter King offers both AC and furnace filters to fulfill all of your clean air needs. You can contact us for a cost quote as we do not list prices for our custom filters.

Who Should Use Custom AC Air Filters

You should use custom air filters if you have an unusually sized unit. We offer odd size furnace filters and custom AC air filters and can make almost any size requested. Not all homes are the same, but you can provide the exact filter dimension for width, length, and depth, select the filter quality, and the amount desired to get what you need. The installation process is the same for custom and standard air filters.

Measuring Filter Dimensions

Filter dimensions include length, width, and depth. You can find them printed in small numbers on Filter King filter frames, but you will want to measure the exact size for a custom air filter.

Begin by checking if the filter is square. If not, measure the smallest side first, then the longer side, and lastly, the depth. Round the measurements up to the nearest whole number when ordering a new filter to make the nominal size. The filter will generally be smaller than the nominal size.

Choosing the Right MERV Rating

We offer MERV rated filter media of 8, 11, and 13 at Filter King. These mid-level ratings have less restricted airflow and do not need frequent changing, and we recommend them for homes, industrial workspaces, and commercial buildings.

MERV 8 is an excellent starting point if no one has respiratory issues and you live in a clean environment. If your household has pets or individuals with asthma or mild allergies, we recommend MERV 11. MERV 13 works well for people with severe breathing issues, newborns, or anyone immunocompromised, and homes in smog-filled cities.

Between 8 and 13, you can expect to block pollen, odors, household dust, dust mites, lint, pet dander, mold spores, and exhaust fumes. MERV 13 can filter virus carriers, including the coronavirus, bacteria, microscopic allergens, and smoke, making it the best filter for your home.

Custom Size Air Filters: Why You Should Trust Filter King

You can trust Filter King to provide premium custom air filters. We want to provide our customers with safe, efficient, and cost-effective filters for their furnace and air conditioning units.

Premium & Long Lasting Custom Air Filters

Our air filters are made with the highest quality materials to ensure their durability and power. They can block airborne particles microns in length and last 3-5 months, which is 3 times longer than most fiberglass filters.

You can get custom air filters of any size, and you can expect them to filter any harmful irritants from your household.

100% Made in the USA

Here at Filter King, we guarantee that we make your air filter and all of its components in the USA. We produce everything in our Alabama warehouse, ensuring your air filter is American-made and effective.

HOME SAFE™ Certified

A Filter King air filter can create a clean, healthy, safe environment for your family to enjoy. We are HOME SAFETM Certified, meaning our products are high-quality and protective. You can expect better smelling and cleaner air by using our filters.

Fast Shipping Guaranteed

We ship directly from our Alabama warehouse within five business days of order for custom air filters. FedEx will then deliver the filter within another five business days if you live in the contiguous United States. We do not offer returns on custom air filters.