24x24x1 air filter
A 24x24x1 filter is square, and most brands cut it to 23 3/8 inches per side. Filtrete lists it close to half an inch larger, at 23.81 to 23.84 inches.
- Printed (nominal)
- 24" x 24" x 1"
- Actual, by brand
- 5 filters listed below
- Spread between brands
- 0.47" wide, 0.47" tall, 0.13" deep
- Face area (nominal)
- 4 sq ft
Actual size by brand
| Brand | Width | Height | Depth | Source |
|---|---|---|---|---|
| Filterbuy | 23.38" | 23.38" | 0.75" | [1] |
| Nordic Pure | 23.38" | 23.38" | 0.75" | [2] |
| AIRx (Discount Filters) | 23.375" | 23.375" | 0.75" | [3] |
| Filtrete Allergen Defense (MPR 1000) | 23.81" | 23.81" | 0.88" | [4] |
| Filtrete High Performance (MPR 1500) | 23.84" | 23.84" | 0.78" | [5] |
MERV options
| Brand | MERV ratings sold at this size | Source |
|---|---|---|
| Filterbuy | 8, 11, 13 | [1] |
| Nordic Pure | 7, 8, 10, 12, 13, 14, 16 | [2] |
| AIRx (Discount Filters) | 7, 8, 11, 13 | [3] |
| Filtrete Allergen Defense (MPR 1000) | 11 | [4] |
| Filtrete High Performance (MPR 1500) | 12 | [5] |
What MERV means: EPA, "What is a MERV rating?"
Listed prices
Prices change often. These are what each seller listed on the date shown.
| Seller | MERV | Pack | Price | Each | Checked | |
|---|---|---|---|---|---|---|
| Nordic Pure | 8 | 6 | $57.49 | $9.58 | Oct 21, 2026 [2] | |
| Discount Filters (AIRx) | 8 | 6 | $74.95 | $12.49 | Oct 21, 2026 [3] | Check price |
| Discount Filters (AIRx) | 11 | 6 | $89.95 | $14.99 | Oct 21, 2026 [3] | Check price |
Printed size vs actual size
24x24x1 is the nominal size printed on the frame. Filterbuy, Nordic Pure and AIRx (sold by Discount Filters) all list the same actual cut, 23 3/8 x 23 3/8 x 3/4 inches (23.38 x 23.38 x 0.75). Filtrete lists its filters larger: the Allergen Defense (MPR 1000, MERV 11) at 23.81 x 23.81 x 0.88 inches, and the High Performance (MPR 1500, MERV 12) at 23.84 x 23.84 x 0.78.
That makes the spread at this size 0.47 inches per side and 0.13 inches in thickness. Filtrete rates its filters by MPR; the MERV numbers above are the ones its listings state.
How to measure your slot
Measure the opening on both sides. A square slot that is a full 24 inches will take any of the brands above, and a Filtrete will leave the smallest gap. If your slot measures under about 23.85 inches, a Filtrete may not go in, so pick one of the 23 3/8 inch cuts. When your number falls between the two groups, buy the smaller 23 3/8 inch filter, because a filter that is too big will not go in at all.
Depth
Every filter here is nominal 1 inch, with real thickness from 0.75 to 0.88 inches. A 24x24x2 is a separate size for a deeper slot. Discount Filters also lists a fiberglass AIRx Equipment Protection filter cut at 23 3/4 x 23 3/4 x 7/8 inches, so check the listing for the exact product you pick.
Questions
What is the actual size of a 24x24x1 filter?
Filterbuy, Nordic Pure and AIRx list 23.38 x 23.38 x 0.75 inches. Filtrete lists 23.81 x 23.81 x 0.88 for its MPR 1000 filter and 23.84 x 23.84 x 0.78 for its MPR 1500 filter.
How big is the difference between brands?
Up to 0.47 inches per side between the 23 3/8 inch cuts and the Filtrete MPR 1500, and up to 0.13 inches in thickness.
Which MERV ratings are sold in 24x24x1?
Filterbuy sells MERV 8, 11 and 13, AIRx sells MERV 7, 8, 11 and 13, Nordic Pure lists MERV 7 to 16, and Filtrete's listings here are MERV 11 and MERV 12.
Similar sizes
Not sure which you have? How to read and measure your filter.
Sources
- Filterbuy 24x24x1 air filter product page, read Oct 21, 2026
- Nordic Pure 24x24x1 air filter product page, read Oct 21, 2026
- Discount Filters 24x24x1 air filters (AIRx), read Oct 21, 2026
- True Value, Filtrete 24 x 24 x 1 1000/1085 MPR Allergen Defense Furnace Filter, MERV 11, read Oct 21, 2026
- True Value, Filtrete High Performance Air Filter, 1500 MPR, 24 x 24 x 1, read Oct 21, 2026