Custom air filters

Custom size air filters — any dimension

Q: Can you get an air filter in any size?

Yes. Custom-cut air filters can be made to virtually any dimension within reason. Standard filter media is cut to your exact specifications, typically within 1/8 inch of your stated dimensions.

Q: How do I measure for a custom air filter?

Measure the filter slot opening at its widest point in each direction — width, height, and depth. Use a metal tape measure for accuracy. Measure twice. For custom orders, use the actual measurements directly, not rounded nominal sizes.

Q: How much do custom air filters cost?

Custom filters typically cost 20-50% more than standard sizes due to individual cutting. However, the cost of an ill-fitting standard filter — which allows unfiltered air bypass — is far higher in HVAC damage and reduced air quality.

Not every home has a standard filter slot. If your dimensions don't match a catalog size, a custom-cut filter is the right answer — not an ill-fitting standard filter that leaves bypass gaps.

Join the waitlist for custom sizes

Custom size ordering launches with the full AirFilterVault store. Enter your email and dimensions and we'll notify you the moment it's available — with your size pre-saved for one-click ordering.

When do you need a custom filter?

You need a custom filter when your slot dimensions don't match any standard nominal size — typically older homes, custom builds, or systems with unusual return air configurations.

Before ordering custom, check: non-standard-looking sizes like 17×21, 15.5×19.5, or 19.75×21 may actually be catalog sizes for specific HVAC brands. Search your exact dimensions first — you may find a standard match.

How to measure for a custom filter

Measure the slot opening

Not the old filter — the slot in your HVAC system. Measure at its widest point in each direction.

Use a metal tape measure

Cloth or flexible tape can sag. Metal tape gives accurate readings to the nearest 1/8 inch.

Measure twice

Confirm both measurements match before ordering. A custom filter cut to wrong dimensions cannot be returned.

Use actual dimensions

Unlike standard orders where you round up to nominal size, custom filters are cut to your exact measurements.

Have a standard size?

If your size matches a standard catalog size, you can order immediately from the size finder.

Find my standard size →

Frequently asked questions

Can you get an air filter in any size?

Yes. Custom-cut filters can be made to virtually any dimension. Standard filter media is cut to your exact specifications, typically within 1/8 inch.

How do I measure for a custom air filter?

Measure the slot opening (not the old filter) at its widest point in each direction. Use a metal tape measure. For custom orders, use actual measurements — not rounded nominal sizes.

How much do custom air filters cost?

Custom filters cost 20-50% more than standard sizes due to individual cutting. The cost of a poorly fitting standard filter — which allows unfiltered air bypass and HVAC damage — is far higher long-term.

Are custom filters available in MERV 11 and 13?

Yes. Custom-cut filters are available in MERV 8, 11, and 13 — the same ratings as standard sizes. Only the dimensions differ.