Filter size finder

Three questions and you have your size. Nothing is sent anywhere — the whole thing runs in your browser, and your answers stay in the address bar so you can bookmark or share the result.

Tool

Step 1

Where is your filter?

A return vent in a wall or ceilingA large grille, usually in a hallway. The filter slides in behind it. Almost always 1 inch.A slot at the furnace or air handlerA thin track at the unit, or a hinged metal box bolted to it. Could be 1, 4, or 5 inches.

Step 2

Measure the filter you have, or the opening.

Round to the nearest quarter inch. Either measurement works — the finder checks your numbers against both the printed size and the actual size.

Width (in)

Height (in)

Depth

The depth is the third number on the frame. A 1 inch filter measures about three quarters of an inch thick.

Step 3

Your size

Enter a width, a height, and a depth and the matching sizes appear here.

All

Every size, if you would rather just look

The number printed on your filter frame is the nominal size, and that is the number to order by. The actual measured size is about half an inch smaller on width and height — that gap is intentional, and it is what lets the filter slide into its track.

1" panel filters

14x20x1actual 13.5 x 19.5 x 0.75
14x25x1actual 13.5 x 24.5 x 0.75
16x20x1actual 15.5 x 19.5 x 0.75
16x25x1actual 15.5 x 24.5 x 0.75
18x18x1actual 17.5 x 17.5 x 0.75
18x24x1actual 17.5 x 23.5 x 0.75
20x20x1actual 19.5 x 19.5 x 0.75
20x24x1actual 19.5 x 23.5 x 0.75
20x25x1actual 19.5 x 24.5 x 0.75
20x30x1actual 19.5 x 29.5 x 0.75
24x24x1actual 23.5 x 23.5 x 0.75
12x24x1actual 11.5 x 23.5 x 0.75

4" and 5" media cabinet filters

16x25x4actual 15.5 x 24.5 x 3.75
20x25x4actual 19.5 x 24.5 x 3.75
20x25x5actual 19.5 x 24.5 x 4.375
16x25x5actual 15.5 x 24.5 x 4.375

Not seeing yours? Odd sizes exist and can be ordered — get in touch.