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Custom Air Filters

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

Reviews from Our Customers

At Filter King, we understand that every HVAC system is unique, which is why we offer custom air filters to fit any size or shape. Our custom air filters are made from high-quality materials, and we offer a range of MERV ratings, from MERV 8 to MERV 13, so you can choose the right filter for your needs.
To order a custom air filter, simply provide us with the dimensions of your existing filter, and we’ll take care of the rest. We offer fast turnaround times and competitive pricing, making it easy and affordable to improve your indoor air quality.

At Filter King, we are committed to providing our customers with the best possible air filtration solutions. If you have any questions about our custom air filters or need help selecting the right filter for your needs, please don’t hesitate to contact us. We are always happy to help!

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.

How to measure your air filter

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.

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.