MERV vs. MPR vs. FPR: air filter ratings explained
One package says MERV 11, another says MPR 1000, and a third says FPR 7. They're three different ways of rating a filter, and only one is an industry standard.
The short answer
- MERV is the industry-standard rating, from a test method published by ASHRAE. Most filter brands use it.
- MPR is a rating created by 3M for its Filtrete filters.
- FPR is a rating created by The Home Depot for filters it sells.
The three don't convert exactly. When you're comparing filters, compare MERV to MERV whenever you can. Many packages that show an MPR or FPR number also list a MERV rating somewhere on the label or product page.
MERV: the industry standard
MERV stands for Minimum Efficiency Reporting Value. It comes from ASHRAE Standard 52.2, a laboratory test that measures how well a filter captures particles in three size ranges: roughly 0.3 to 1 micron, 1 to 3 microns, and 3 to 10 microns. The results are turned into a single number on a scale of 1 to 16. Higher numbers mean better capture of small particles.
For home furnaces and central air, filters typically range from about MERV 5 to MERV 13. Because MERV is a published standard used across many brands, it's the most reliable way to compare filters from different makers. Our guide to MERV 8 vs. 11 vs. 13 helps you pick a level.
MPR: 3M's rating
MPR stands for Microparticle Performance Rating. 3M uses it on Filtrete-brand filters. It focuses on how well a filter captures very small particles, between 0.3 and 1 micron. MPR numbers run in the hundreds and thousands, such as 300, 1000, or 1900. Filtrete packages usually show a MERV rating alongside the MPR number. A higher MPR means better capture of those small particles.
MPR is a brand rating, not an independent industry standard, so it's mainly useful for comparing one Filtrete filter with another.
FPR: The Home Depot's rating
FPR stands for Filter Performance Rating. The Home Depot created it for filters sold in its stores, including several brands. On packages it usually appears as a number from 4 to 10, often with a color code. FPR combines how well a filter catches large and small particles, along with how much dust it holds over its life. A higher FPR means more filtration.
Like MPR, FPR is a retailer's rating rather than an industry standard. It's handy for comparing filters on the same shelf but harder to compare with other retailers' products.
Rough comparison
There's no official conversion between the three scales, since each uses its own test method. The table below lines them up the way the brands themselves pair them on their packaging and websites. Treat it as a rough guide. If a package lists a MERV rating, go by that.
| MERV | MPR (approx.) | FPR (approx.) | Typical use |
|---|---|---|---|
| 5–7 | about 300–600 | below 4–5 | Basic filtration |
| 8 | about 700 | about 4–5 | Good everyday choice |
| 10–11 | about 1000–1200 | about 6–9 | Pets and allergies |
| 12 | about 1500 | about 9 | Higher filtration |
| 13 | about 1900–2200 | about 10 | Highest for most home systems |
Approximate and unofficial. Different products with the same MPR or FPR number can test differently, so check the product's own rating details before you buy.
Higher isn't automatically better
Whatever the scale, a higher number generally means denser filter material. In a thin 1-inch filter, that can restrict airflow in systems not designed for it. Before moving to the top of any scale, check your HVAC manual or ask a technician. If your system has room for a thick media filter, it can offer higher filtration with less restriction. See 1-inch vs. 4-inch air filters.
What about HEPA?
HEPA is a separate, much stricter standard for very high-efficiency filters. It's not part of the MERV scale. True HEPA filters are very dense, and standard home HVAC systems generally aren't built to push air through them. Using HEPA with central air usually means a dedicated system installed by a professional. Portable HEPA air purifiers are a separate option for individual rooms.
How to compare filters in practice
- Get the size right first, including depth. See how to find your air filter size.
- Look for a MERV number on every option, including the fine print and the product page.
- Compare MERV to MERV. If one product lists only MPR or FPR, use the rough bands above as a starting point.
- Check your system's limits in the manual before going above MERV 8 in a 1-inch filter.
- Factor in the change schedule. Higher-rated filters can fill up sooner. See how often to change your air filter.
FAQ
Is MPR 1000 the same as MERV 11?
They're usually paired that way. Filtrete MPR 1000 filters are generally labeled MERV 11. The two scales measure different things, though, so there's no exact conversion. When in doubt, read the MERV number on the package.
Is FPR 10 the best filter?
It's the top of The Home Depot's scale, meaning the most filtration in that line. It's not the best choice for every system. Check that your system can handle a high-efficiency filter first.
Why don't all brands just use MERV?
Brands and retailers sometimes create their own scales to highlight specific results or simplify shopping. MERV remains the common standard, so it's the best number to compare across brands.
This guide is general information, not professional HVAC advice. Your equipment manual and filter packaging take priority. Some links on this site may be affiliate links. See our affiliate disclosure.