MERV vs MPR vs FPR: Air Filter Rating Converter
Air filter ratings can be confusing. Three different systems rate the same thing, and each brand uses a different one. This converter shows you the equivalent rating across all three so you can compare filters from any store.
Select what you know
Full MERV / MPR / FPR Conversion Chart
| MERV | MPR | FPR | Captures |
|---|---|---|---|
| 1-4 | 100-300 | 4 | Pollen, dust mites, carpet fibers |
| 5-8 | 300-600 | 5-6 | Mold spores, pet dander, dust |
| 9-11 | 600-1000 | 7 | Fine dust, lead dust, auto emissions |
| 12 | 1000-1500 | 8-9 | Legionella, humidifier dust |
| 13-14 | 1500-1900 | 10 | Bacteria, smoke, virus carriers |
| 15-16 | 2200+ | 10+ | All fine particles (hospital grade) |
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Open Filter Finder →What is MERV?
MERV stands for Minimum Efficiency Reporting Value, established by ASHRAE (the American Society of Heating, Refrigerating and Air-Conditioning Engineers). It rates a filter's ability to capture particles between 0.3 and 10 microns on a scale of 1 to 16. Higher MERV = finer filtration. Most residential filters fall between MERV 8 and MERV 13. MERV is the industry standard and the most reliable way to compare filters across brands.
What is MPR?
MPR stands for Micro-Particle Performance Rating. It's a proprietary system created by 3M and used exclusively on their Filtrete brand filters. MPR focuses on particles smaller than 1 micron (which MERV doesn't directly test for), making it useful for comparing Filtrete models. MPR values range from 100 to 2800+. While MPR roughly maps to MERV, it's not an exact 1:1 conversion because the test methods differ.
What is FPR?
FPR stands for Filter Performance Rating. It's Home Depot's proprietary rating scale, used on filters sold in their stores. FPR runs from 4 to 10 and uses a color-coded system: green (FPR 4-5) for basic, yellow (FPR 7) for better, and red (FPR 9-10) for best. FPR gives a simpler number, but it only applies to Home Depot filters.
Which rating should I trust?
MERV is the most reliable because it's an independent industry standard, not tied to any one brand or retailer. When shopping across stores and brands, compare by MERV rating. If you're buying Filtrete specifically, MPR gives you finer granularity between their product lines. FPR is only useful when shopping at Home Depot and comparing their in-store options.