Quick answer: MERV vs MPR vs FPR are three rating systems for the same thing: how well a filter catches particles. MERV is the universal industry standard (1–16). MPR is 3M Filtrete's in-house scale. FPR is The Home Depot's store scale. When comparing filters, convert everything to MERV, the only rating tested under the neutral ASHRAE 52.2 standard.
Walk down the filter aisle and you'll see three different number systems shouting at you. One filter brags "MPR 1500," another says "FPR 10," a third lists "MERV 13." They're all measuring filtration, but they're not the same scale, and that's exactly how it gets confusing. This guide on MERV vs MPR vs FPR makes them line up so you can compare apples to apples.
MERV vs MPR vs FPR: what each one means
MERV (Minimum Efficiency Reporting Value)
MERV is the industry standard, used across the whole HVAC world. It runs from 1 to 20 and is set by testing under the neutral ASHRAE 52.2 standard. Because it's independent and universal, MERV is the rating you can trust to compare any two filters from any brand. For homes, the useful range is MERV 8 to 13.
MPR (Microparticle Performance Rating)
MPR is a proprietary scale created by 3M for its Filtrete line. It runs from about 300 to 2800 and focuses on the tiniest particles (0.3 to 1 micron). The big numbers look impressive, but they only exist on 3M products. You can't directly compare an MPR to another brand's rating without converting to MERV first.
FPR (Filter Performance Rating)
FPR is a scale used by The Home Depot for its store-brand and exclusive filters. It runs from 4 to 10 and uses a color-code system. Like MPR, it's a retailer's own scale, so it only helps you compare filters sold under that program.
Why three systems exist
It comes down to marketing. MERV is neutral and standardized, which is great for shoppers but doesn't let any one brand stand out. So 3M and The Home Depot built their own scales with bigger, flashier numbers. An "MPR 1900" sounds more powerful than "MERV 13," even though they're roughly the same filter. The proprietary scales also lock you into comparing within a single brand or store.
Our advice: ignore the marketing scale and find the MERV. Every honest filter listing tells you, or can be converted. Ironside rates everything in plain MERV so there's nothing to decode.
MERV vs MPR vs FPR conversion chart
Use this to translate any rating into the universal MERV scale. Values are approximate, since the scales don't line up perfectly, but this is close enough to shop confidently:
| MERV | MPR (3M Filtrete) | FPR (Home Depot) | Catches |
|---|---|---|---|
| MERV 8 | MPR 600–800 | FPR 5–6 | Dust, pollen, lint |
| MERV 11 | MPR 1000–1200 | FPR 7 | Pet dander, mold spores, smog |
| MERV 13 | MPR 1500–1900 | FPR 10 | Smoke, bacteria, fine particles |
So that scary-sounding "MPR 1900" filter is really just a MERV 13. And MERV 13 is the highest most residential systems handle. For the differences between the common MERV levels, see MERV 8 vs 11 vs 13.
Which rating should you shop by?
Shop by MERV. Always. Here's why:
- It's universal. MERV works across every brand and retailer, so you're never locked in.
- It's independently tested. ASHRAE 52.2 is a neutral standard, not a marketing department.
- It's honest about the number. A four-digit MPR isn't four times better than a two-digit MERV. It's just a bigger-looking number for the same job.
When you see MPR or FPR, run it through the chart above to find the real MERV, then compare. Need help choosing the level itself? Our guide to what MERV rating you need matches it to your home.
One thing no rating covers: odors
MERV, MPR, and FPR all measure particle capture. None of them measure odor control. If you want to cut cooking smells, pet odors, or smoke smell, you need an activated-carbon layer, which absorbs odors and VOCs but does not raise the particle rating. Learn more in what is a carbon air filter, or shop the Odor & Smoke collection.
Shop by MERV at Ironside
We keep it simple. Every Ironside filter lists a straight MERV rating, so there's no decoder ring required. Pick your level:
- Everyday Defense (MERV 6–8) for dust and pollen
- Allergy & Pet (MERV 10–12) for dander and allergies
- Maximum Protection (MERV 13–16) for smoke and fine particles
- Or browse all filters
Know your size first with the size finder, then set up a subscription so the right filter arrives on schedule with free shipping every order and your price locked in.
FAQ
Is MERV better than MPR or FPR?
MERV isn't a "better filter," it's a better rating system. It's the neutral industry standard tested under ASHRAE 52.2 and used across all brands. MPR (3M) and FPR (Home Depot) are proprietary scales. Convert MPR and FPR to MERV when comparing, and shop by MERV.
What MERV is MPR 1900?
An MPR of roughly 1500 to 1900 corresponds to about MERV 13, which catches smoke, bacteria, and fine particles. The big MPR number is mostly marketing. It's the same level of filtration as a MERV 13 filter from any brand.
What MERV is FPR 10?
FPR 10 corresponds to about MERV 13. The Home Depot's FPR scale tops out at 10, which lines up with about MERV 13. MERV 14–16 filters, like our Maximum Protection line, have no FPR equivalent — the store scales don't go that high. Convert it to MERV 13 when comparing against other brands.
Do any of these ratings measure odor removal?
No. MERV, MPR, and FPR all measure particle capture only. To control odors, VOCs, or smoke smell, you need an activated-carbon filter. Carbon absorbs gases but does not change the particle rating, so look for a filter that lists both.