FilterBySize Furnace and AC filter sizes, actual dimensions, MERV

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24x24x1 air filter: actual size, MERV, and price

A 24x24x1 is a one-inch-class square furnace or AC filter. Buy the printed size 24x24x1. The panel is smaller than 24 inches on each face — Filtrete closer to 23.68 × 23.68 × 0.81 or 23.81 × 23.81 × 0.78, and Nordic Pure about 23.38 × 23.38 × 0.75. Do not substitute 20x20x1 — that is a different printed size.

Actual size by brand

These numbers are copied from manufacturer or merchant product copy, not from a competitor size chart. Thickness is part of the fit: 1-inch racks take ~¾ inch media.

Brand Nominal Published actual (in.) Source
Filtrete 24x24x1 MPR 1000 / MERV 11 24x24x1 23.68 × 23.68 × 0.81 Amazon B07CQGMDV6 title and product-dimensions field “23.68 × 23.68 × 0.81”; B07FP5X2TF title “Actual Size 23.68 × 23.68 × 0.81 in”
Filtrete 24x24x1 MPR 1000 / MERV 11 (some listings) 24x24x1 Title: 23.69 × 23.69 × 0.81; 6-pack dimensions field also 23.81 × 23.81 × 0.81 Amazon B09YXYBJSY title “Actual Size 4-Pack 23.69×23.69×0.81 in”; B07FP5X2TF product-dimensions field lists 23.81 × 0.81 × 23.81 — two figures on the same family; measure if the slot is tight
Filtrete 24x24x1 MPR 700 / MERV 8 24x24x1 23.81 × 23.81 × 0.81 Amazon B0DMTH8H1F title “Actual Size 23.81 × 23.81 × 0.81 in”; product-dimensions field lists 23.81 × 23.81 × 0.81
Filtrete 24x24x1 MPR 1900 / MERV 13 24x24x1 23.81 × 23.81 × 0.78 Amazon Filtrete store 24x24x1 titles for MPR 1900 2-pack and 6-pack “Act Size 23.81×23.81×0.78 in”
Nordic Pure 24x24x1 pleated 24x24x1 Approximately 23.38 × 23.38 × 0.75 (23⅜ × 23⅜ × ¾) JB Tools listings for Nordic Pure 24x24x1M8-6 and 24x24x1M13-6

We did not find a Honeywell Store 24x24x1 1-inch SKU (MERV 8/11/13 4-pack or 12-pack) that publishes actual dimensions, so that brand is omitted rather than guessed. We did not find an Amazon Basics 24x24x1 listing that publishes an actual-size field, so that brand is omitted rather than guessed. If you currently run Nordic Pure (~23.38 square) and switch to Filtrete (~23.68 or 23.81 square), expect a snugger slide-in. Filtrete’s published actuals also disagree with each other by SKU. Measure the old filter if the slot is tight. Full method: how to measure.

MERV 8 vs 11 vs 13 (facts only)

MERV is ASHRAE 52.2, as summarized by EPA. Higher MERV captures a larger share of smaller particles. It also adds resistance. EPA says to pick at least MERV 13 or as high a rating as your system fan and filter slot can accommodate, and to ask an HVAC technician if you are unsure. A 1-inch MERV 13 is not HEPA. We do not claim health outcomes.

MERV EPA average capture efficiency (particle size) Typical 24x24x1 use
8 ≥20% of 1.0–3.0 µm; ≥70% of 3.0–10.0 µm Common pleated replacement when the manual does not call for higher
11 ≥20% of 0.30–1.0 µm; ≥65% of 1.0–3.0 µm; ≥85% of 3.0–10.0 µm Mid-grade 1-inch pleat (Filtrete MPR 1000 is commonly labeled MERV 11)
13 ≥50% of 0.30–1.0 µm; ≥85% of 1.0–3.0 µm; ≥90% of 3.0–10.0 µm Higher-efficiency 1-inch; confirm the furnace/air handler can take the extra pressure drop

Source: U.S. EPA, “What is a MERV rating?”, last updated 14 Jan 2026. Filtrete also prints an MPR number; MPR is 3M’s scale, not MERV. Compare MERV to MERV.

Pack prices checked 30 Aug 2026

These are public shelf/cart prices we recorded on 30 Aug 2026. They are not live. Shipping, subscribe-and-save, and store-only deals will move them. Per-filter math is pack price ÷ count, rounded to the cent.

Listing MERV Pack Price that day Per filter Merchant
Nordic Pure 24x24x1 pleated (reseller) 8 2 $30.14 $15.07 JB Tools
Nordic Pure 24x24x1 pleated (reseller) 8 6 $51.74 $8.62 JB Tools
Nordic Pure 24x24x1 pleated (reseller) 13 2 $34.19 $17.10 JB Tools
Nordic Pure 24x24x1 pleated (reseller) 13 6 $71.99 $12.00 JB Tools

Observed range that day for ordinary pleated 24x24x1: about $8.62/filter at MERV 8 in a Nordic Pure 6-pack, $12.00 at MERV 13 in a Nordic Pure 6-pack, with 2-packs costing more per filter ($15.07 MERV 8; $17.10 MERV 13). Honeywell Store product URLs for 24x24x1 MERV 8/11/13 4-packs and 12-packs returned 404, so those rows are omitted rather than guessed. Target listed a Filtrete 24x24x1 MPR 1000 1-pack (A-15113307); that product page and Target’s price API returned a bot check or no public cart price, so that pack price is omitted rather than guessed. Walmart Filtrete product pages returned a bot check, so those pack prices are omitted rather than guessed. Amazon Filtrete pages were used for actual-size fields, not for this price table. Amazon Basics had no published 24x24x1 actual-size listing. Nordic Pure’s own 24x24x1 factory cart was not used for a 1-inch SKU in this check; the JB Tools figures are reseller snapshots. A 24x24x1 is not a 20x20x1.

Where to buy

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No ranking. Stock and price change. If the slot is an odd fraction that none of these actual sizes match, measure first — that is not a 24x24x1 SKU. A 20x20x1 is not a substitute.

Sources (accessed 30 Aug 2026)