MERV is the real industry standard (ASHRAE 52.2), rated 1–20 by how well a filter captures particles of different sizes. FPR (Home Depot's in-house scale, 4–10) and MPR (3M Filtrete's in-house scale, up to ~2800) are brand-proprietary scales mapped to MERV — they exist mainly for in-store shopping, not as independent standards.
Which rating do I need? MERV 8 covers common household allergens (dust, pollen, pet dander) and is the standard pick for most homes. MERV 11–13 adds finer allergens, bacteria, and most smoke — a common step-up for allergy sufferers or homes with pets. MERV 13+ approaches virus-carrier particle filtration. Going higher than your HVAC system is rated for can restrict airflow, so check your system's manual if you're jumping above MERV 13.
Common mix-up: Filtrete MPR 1500 sounds like it should mean MERV 15 — it actually corresponds to about MERV 12.
| MERV | FPR | MPR | Catches |
|---|---|---|---|
| MERV 5 | — | 300 | Large particles: dust, lint, some pollen |
| MERV 6 | 4 | — | Household dust, pollen, larger mold spores |
| MERV 7 | — | 600 | Household dust, mold spores, pollen, dust mite debris |
| MERV 8 | 5 | — | Common household allergens: dust, pollen, pet dander |
| MERV 9 | — | — | Finer dust, trace auto emissions |
| MERV 10 | 6–7 | — | Fine dust, pet dander, mold spores, auto emissions |
| MERV 11 | 8 | 1000–1200 | Finer dust, pet dander, mold spores, some bacteria |
| MERV 12 | 9 | 1500 | Allergens, bacteria, virus-carrier particles |
| MERV 13 | 10 | 1900–2200 | Fine particulates, bacteria, most smoke |
| MERV 14 | — | 2500–2800 | Ultrafine particles, smoke, bacteria/viruses |
| MERV 15 | — | — | Very fine particulates — approaching HEPA-level on smoke-size particles |
| MERV 16 | — | — | Near-HEPA performance across dust, pollen, smoke and bacteria-size particles |
Know your filter size? Look it up in the full FilterKey tool.