20x25x4 air filter
Generic 20x25x4 filters measure 19.44 to 19.88 by 24.44 to 24.56 inches, and from 3.63 to 4.31 inches thick. AprilAire's own 20x25x4 media is larger than the printed size.
- Printed (nominal)
- 20" x 25" x 4"
- Actual, by brand
- 7 filters listed below
- Spread between brands
- 0.44" wide, 0.12" tall, 0.69" deep
- Face area (nominal)
- 3.47 sq ft
Actual size by brand
| Brand | Width | Height | Depth | Source |
|---|---|---|---|---|
| Filterbuy | 19.5" | 24.5" | 3.63" | [1] |
| Nordic Pure | 19.5" | 24.5" | 3.63" | [2] |
| AIRx ALLERGY MERV 11 (Discount Filters) | 19.5" | 24.5" | 3.625" | [3] |
| AIRx HEALTH MERV 13 (Discount Filters) | 19.5" | 24.5" | 3.75" | [4] |
| Filtrete Allergen Defense (MPR 1000) | 19.88" | 24.56" | 4.31" | [6] |
| Filtrete Ultra Allergen (MPR 1550) | 19.88" | 24.56" | 4.31" | [7] |
| Filtrete Slim Fit (MPR 1550) | 19.44" | 24.44" | 3.69" | [8] |
MERV options
| Brand | MERV ratings sold at this size | Source |
|---|---|---|
| Filterbuy | 8, 11, 13 | [1] |
| Nordic Pure | 7, 8, 10, 12, 13, 14, 15 | [2] |
| AIRx (Discount Filters) | 11, 13 | [5] |
| Filtrete Allergen Defense (MPR 1000) | 11 | [6] |
| Filtrete Ultra Allergen (MPR 1550) | 12 | [7] |
| Filtrete Slim Fit (MPR 1550) | 12 | [8] |
| AprilAire 210 (cabinet media) | 11 | [9] |
| AprilAire 213 (cabinet media) | 13 | [10] |
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 | $124.99 | $20.83 | Oct 21, 2026 [2] | |
| Discount Filters (AIRx) | 11 | 6 | $174.95 | $29.16 | Oct 21, 2026 [3] | Check price |
| Nordic Pure | 13 | 6 | $169.99 | $28.33 | Oct 21, 2026 [2] |
Printed size vs actual size
20x25x4 is a nominal size. Filterbuy, Nordic Pure and AIRx all list a 19.5 x 24.5 inch face. Filterbuy and Nordic Pure list 3 5/8 inches (3.63) of depth. AIRx lists 3 5/8 for its MERV 11 filter and 3 3/4 for its MERV 13, so depth can change within one brand. Filtrete's standard deep pleat filters are larger, 19.88 x 24.56 x 4.31 inches, while its Slim Fit is the smallest listing here at 19.44 x 24.44 x 3.69.
Across these listings the face differs by 0.44 inches in width and 0.12 inches in height, and the depth by 0.69 inches. On a 4 inch filter the depth is often the deciding number. Filtrete rates by MPR; the MERV figures above are the ones its listings state.
Cabinet media is not the same part
AprilAire's 210 (MERV 11) and 213 (MERV 13) are sold for its own air purifier cabinets as nominal 20 x 25 x 4, but AprilAire lists their actual size as 20.6 x 26.63 x 4 inches. That is larger than the printed size and much larger than any generic cut here. If your filter goes in an AprilAire cabinet, order by part number.
How to measure your slot
Measure the face and the depth of the opening. If the slot takes a full 4.31 inches, any generic filter here fits. If it is closer to 3.7 inches, pick a 3.63 inch cut or the Filtrete Slim Fit. If your face measurement lands between 19.5 and 19.88, the 19.5 inch cut is the one that will go in.
Equipment that takes this size
- Aprilaire 2210 (media cabinet)
- Honeywell Home F100F2025 (media cabinet)
Questions
What is the actual size of a 20x25x4 filter?
Filterbuy, Nordic Pure and AIRx list a 19.5 x 24.5 inch face at 3.63 to 3.75 inches deep. Filtrete lists 19.88 x 24.56 x 4.31 for its standard deep pleat filters and 19.44 x 24.44 x 3.69 for its Slim Fit.
Does a generic 20x25x4 replace an AprilAire 210 or 213?
Not by size. AprilAire lists the 210 and 213 at 20.6 x 26.63 x 4 inches actual, larger than any generic 20x25x4 on this page.
How much do 20x25x4 filters differ in depth?
From 3.63 inches (Filterbuy, Nordic Pure, AIRx MERV 11) to 4.31 inches (Filtrete standard), a difference of 0.69 inches.
Similar sizes
Not sure which you have? How to read and measure your filter.
Sources
- Filterbuy 20x25x4 air filter product page, read Oct 21, 2026
- Nordic Pure 20x25x4 air filter product page, read Oct 21, 2026
- Discount Filters, 20x25x4 AIRx ALLERGY Air Filter MERV 11, 6-Pack, read Oct 21, 2026
- Discount Filters, 20x25x4 AIRx HEALTH Air Filter MERV 13, 6-Pack, read Oct 21, 2026
- Discount Filters 20x25x4 standard filters, read Oct 21, 2026
- True Value, Filtrete 20 x 25 x 4 1000 MPR Allergen Defense Deep Pleat Furnace Filter, MERV 11, read Oct 21, 2026
- True Value, Filtrete Ultra Allergen Reduction Deep Pleat Filter, 20 x 25 x 4, read Oct 21, 2026
- True Value, Filtrete 20 x 25 x 4 1550 MPR (Slim Fit) Deep Pleat Furnace Filter, MERV 12, read Oct 21, 2026
- AprilAire 210 MERV 11 Air Filter, read Oct 21, 2026
- AprilAire 213 MERV 13 Air Filter, read Oct 21, 2026