01Floor
Width × Length
Measure the inside width across the opening, then measure the inside length from end to end.
Example4 in × 10 in
Shop Floor Vent Covers
Measuring Guide
How to Measure for a Vent Cover
The correct vent size starts with the duct opening. Remove the existing cover and measure the opening itself before selecting a floor, wall or ceiling vent cover.
Measure the duct opening, not the old vent cover.
Remove the existing cover first, then measure from one inside edge of the opening to the opposite inside edge.
Inside opening only
Use inches
Keep exact fractions
The Most Important Rule
Start with the opening itself.
The outside dimensions of an existing grille or vent cover can be larger than the duct opening. Those outside dimensions are not the size you should use when selecting an Airwinks vent cover.
Correct: inside edge to inside edge of the duct opening.
Measurement Format
Use the format for your installation surface.
The measuring method is the same: measure inside edge to inside edge. The way the dimensions are written depends on whether the opening is in the floor, wall or ceiling.
02Wall
Width × Height
Measure the inside width from side to side, then measure the inside height from top to bottom.
Record asWidth × Height
Shop Wall Vent Covers
03Ceiling
Width × Height
Measure both inside dimensions of the ceiling opening edge to edge and record them in the listed order.
Record asWidth × Height
Shop Ceiling Vent Covers
Step by Step
Four steps before choosing a size.
A tape measure and the exposed duct opening are all you need for a standard measurement.
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1
Remove the existing cover
Expose the actual duct opening. Do not measure across the face, flange or outside perimeter of the old cover.
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2
Measure the inside width
Place the tape at one inside edge of the duct and measure straight across to the opposite inside edge.
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3
Measure the second dimension
For a floor opening, measure the inside length. For a wall or ceiling opening, record the second dimension as height.
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4
Write down the exact measurement
Use inches and keep any fraction you see. Do not round the opening to a different listed size.
Size Example
A 4 inch × 10 inch floor opening means you shop the 4x10 size.
The measurement comes from the duct opening. The old cover itself may have larger outside dimensions.
Browse Floor Vent SizesAvoid These Mistakes
What not to measure.
The outside of the old cover
The visible cover is normally larger than the opening it sits over or inside.
The outer flange or trim
Start and stop the tape at the inside duct edges, not decorative or mounting edges.
A rounded measurement
If the opening includes a fraction, record the fraction rather than changing it to a nearby whole number.
An assumed size from memory
Remove the cover and verify the opening even when you think you already know the vent size.
After Measuring
Match the opening to a listed size, or request a custom size.
If your exact inside opening measurement appears in the appropriate Airwinks collection, choose that listed size. If it does not, send the exact measurements for custom-size review.
Measurement FAQ
Questions before you order.
Should I measure my existing vent cover?
No. Remove the existing cover and measure the inside duct opening from one inside edge to the opposite inside edge.
What order should I write the measurements?
For floor vents, use width × length. For wall and ceiling vents, use width × height.
What if my measurement includes a fraction?
Write down the exact fraction. Do not round the duct opening to another size.
What if my duct opening is square?
Measure both inside dimensions even when they appear equal, then compare the result with the listed square sizes for the installation surface.
What if my opening does not match a listed Airwinks size?
Use the Custom Size Vent Covers page to submit the exact inside-opening dimensions and installation details for review.
Should I take a photo of the opening?
A photo is useful when the opening is unusual, includes fractions, or is being submitted for a custom-size review.
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