MERV vs FPR vs MPR: Filter Ratings Explained
Three different numbers on three different boxes — often the same filters. Here's how to translate MERV, FPR, and MPR and shop with confidence.
You are standing in the filter aisle. One box says MERV 11, another says MPR 1000, a third says FPR 7 - and they all claim to be best. It is confusing by design. The good news: these are mostly three different ways of describing the same thing. Once you know that MERV is the neutral industry standard and the other two are store-specific scales, the fog lifts. Here is how to read all three and translate them into one number you can trust across every brand.
Why are there three rating systems?
Because two big retailers built their own. MERV came first and is the neutral, industry-wide benchmark. Then 3M created MPR for its Filtrete line, and The Home Depot created FPR for the brands on its shelves. Neither proprietary scale is dishonest - but they make it harder to compare a box on one store's shelf against a competitor's somewhere else. The fix is simple: translate everything back to MERV.
What is MERV?
MERV stands for Minimum Efficiency Reporting Value. It is the standard developed by ASHRAE, the engineering society for heating and air professionals, and it is the only one of the three based on independent, standardized testing. MERV measures how well a filter captures particles across a range of sizes - roughly 0.3 to 10 microns - on a scale of 1 to 16, with residential filters typically running 1 to 13. The higher the number, the finer the particles captured. Because it is universal, MERV appears on filters from virtually every manufacturer, including the AAF Flanders and Koch lines we carry. When you compare across brands, MERV is the number to trust - you can shop our full catalog by MERV rating directly.
What are MPR and FPR?
MPR (3M Filtrete) stands for Microparticle Performance Rating, a system 3M created exclusively for its Filtrete filters. It focuses on the smallest particles - those under 1 micron - and runs from roughly 300 to 2800. Because it emphasizes the particle sizes where Filtrete tests well, MPR numbers look large, but they only mean something within the Filtrete line. No other brand uses MPR.
FPR (The Home Depot) stands for Filter Performance Rating, a color-coded scale running from 4 to 10 that appears on Honeywell and other brands sold in their stores. FPR factors in more than particle capture alone - it also weighs things like how much dust a filter holds over its life - which is why FPR-to-MERV conversions can disagree by a step depending on the source.
The cross-reference table
Here is the practical translation. Treat these as approximate ranges - close enough to shop confidently, but not precise equations:
| MERV | FPR | MPR | Best for |
|---|---|---|---|
| MERV 6 | FPR 4 | MPR 300 | Basic dust and lint, budget |
| MERV 8 | FPR 5 | MPR 600 | Everyday home baseline |
| MERV 11 | FPR 7 | MPR 1000-1200 | Pets and allergy households |
| MERV 13 | FPR 10 | MPR 1900 | Allergies, smoke, fine particles |
The most common aisle mix-up: a filter labeled "Filtrete 1000" is MPR 1000, which translates to roughly MERV 11 - not MERV 10. The big proprietary numbers are not MERV numbers. When in doubt, look for the small-print MERV equivalent on the box and compare on that. Our companion piece comparing MERV, FPR, and MPR walks through more examples.
Which rating should you actually use?
For shopping, use MERV every time - it is the one number that works across every brand and store. Then match it to your home:
- MERV 8 for a clean home with no pets or allergies - solid everyday protection.
- MERV 11 if you have pets or mild allergies - the popular step up.
- MERV 13 for allergy or asthma sufferers, smoke, or wildfire season - if your system supports it.
Higher is not automatically better. A filter rated beyond what your system is designed for can restrict airflow and make your blower work harder - our explainer on why higher MERV is not always better covers the tradeoff. For a deeper dive into the scale itself, see our MERV ratings explained and how to select the right filter by MERV. Check your system's maximum in the owner's manual or on the cabinet label before going above MERV 11. You can browse our full range of MERV 13 pleated filters once you have confirmed your system can handle them, across our air filters and furnace filters collections.
Frequently asked questions
Is MERV, MPR, or FPR better?
None is "better" - they often describe the same filters. MERV is the only independent, industry-wide standard, so it is the most reliable for comparing across brands. MPR and FPR are proprietary scales from 3M and Home Depot respectively.
What MERV is MPR 1000?
MPR 1000 translates to roughly MERV 11 - a step up from MERV 8, not equal to it. This is the most common point of confusion when shopping Filtrete filters.
What MERV is FPR 7?
FPR 7 is approximately MERV 11. Because FPR also factors in dust-holding capacity, conversions can vary by a step between sources, but MERV 11 is the standard equivalent.
What MERV rating do I need for my home?
Most homes do well at MERV 8 to 13. Choose MERV 8 for a clean home, MERV 11 for pets or mild allergies, and MERV 13 for allergy sufferers, smoke, or wildfire season - provided your system can handle it. Always check your system's maximum first.