Start with the printed size
The size printed on the filter is usually a nominal size. Confirm that label and the filter depth before shopping.
An independent guide to home HVAC filters
Buy the right size.
Understand what matters.
Start with the three dimensions on your current filter. Learn how nominal size and MERV ratings work, and see exactly what FilterMatch has—and has not—verified.
✓ Practical sizing guide✓ Primary-source references✓ No made-up offers
01 / Start with the label
What size is on your filter?
Your shortlist
Try a size to see matched options
Search by the three numbers on your filter. We’ll show verified listings here when they are available.
FilterMatch may earn a commission from qualifying purchases after affiliate links are added. This does not affect fit evidence or ranking.
Live retailer searches
Check current retailer listings
These links open the retailer’s own search results for your size. FilterMatch does not ingest or verify the products, fit, price or stock shown there. These are direct, non-affiliate links; FilterMatch earns no commission from them.
How FilterMatch works
Useful guidance.
Careful claims.
FilterMatch is being built around a simple rule: a product should not be called a match unless the dimensions and supporting evidence are clear. No retailer listings are live yet.
Check the rating system
MERV, MPR and FPR are different rating systems. We keep the system name alongside the number.
Read the evidence
When verified products become available, each listing will show its source, fit evidence and last-checked date.
Field guide · 01
How to find your HVAC filter size
Three numbers, one frame, and a small distinction that prevents a frustrating return.
Look for the printed dimensions
Switch the HVAC system off before opening the filter slot. The size is commonly printed on the cardboard frame as width × height × depth—for example, 16 × 25 × 1 inches. Check the old filter and the equipment manual before ordering.
Nominal is not always measured
The printed size is often a nominal size used to identify a filter. Some products also state their exact physical dimensions; these can vary by product. If your slot is tight, check the manufacturer's dimensions instead of assuming every filter with the same label measures identically.
Measure only when the label is missing
If the label is unreadable, remove the filter and record its width, height and depth as accurately as you can. Do not round or substitute those measurements until you know whether a listing asks for nominal or exact dimensions. Never bend, crush or force a filter into place; it should fit snugly without gaps.
For an unfamiliar filter slot or uncertain size, use the system manual or ask an HVAC professional to confirm the replacement. EPA: Guide to Air Cleaners in the Home · Purolator: filter-size FAQ.
Field guide · 02
What a filter rating can—and cannot—tell you
A rating is one useful specification. It does not, by itself, tell you whether a filter is right for your system.
A standardized scale
MERV means Minimum Efficiency Reporting Value. It describes a filter’s particle-removal performance under a defined test method. Higher MERV values indicate greater capture efficiency for many particle sizes, but system compatibility still matters.
Different labels, different systems
MPR and FPR are proprietary rating systems used by particular brands. Do not read a number from one system as if it were the same number in another. Compare the named system and consult product documentation.
Follow the equipment guidance
A more restrictive filter can affect airflow. The EPA advises choosing a filter that the system fan and slot can accommodate and suggests consulting an HVAC professional when unsure about the highest suitable rating.
Sources: EPA: What is a MERV rating? · EPA: HVAC system filters · ASHRAE Handbook: Air filters.
Field guide · 03
A quick check before you order
Use this short checklist to compare like with like and avoid guessing at fit.
Coverage, at a glance
Know what we checked.
The source registry tracks one public EPA guidance page. Other technical references are linked with the relevant guides. Retailer searches open current results on retailer websites, but no product feed is ingested and no retailer offer has been verified by FilterMatch.
1guidance source in the registry
0authorized retailer feeds
0verified live offers
Registry reviewed: 18 Oct 2026. Discovery is limited; no claim of complete web coverage.
About FilterMatch. FilterMatch is an independent US home-maintenance guide to HVAC filter dimensions and ratings. It offers sizing guidance and, after a visitor searches, direct links to live retailer search pages. Those retailer results are not copied into FilterMatch or verified for fit, price or stock. FilterMatch currently has no product-feed listings or endorsements.
Affiliate disclosure. The current Home Depot, Lowe’s and Amazon search links are direct links, not affiliate links, and FilterMatch earns no commission from them. If FilterMatch later adds approved tracked links, it will disclose the relationship beside them. Commercial relationships will not determine whether a filter is described as a fit.
Privacy note. The site has no account or email sign-up. A size search opens retailer search links using the dimensions entered. When the FilterMatch catalogue service is connected, a size search may also be sent to it to look for exact-size results. FilterMatch does not ask for health or household-identifying information. Standard technical data may be processed by the site host to serve and protect the website.
Important fit note. A higher-efficiency filter may not be suitable for every HVAC system. Consult your system manual or a qualified technician when compatibility is uncertain. This guide is not medical advice and makes no health outcome claims.