Measuring Guide

How to Measure Vent Covers

Measure the inside duct opening, not the outside face of the old vent cover or register. Record floor openings as width × length, wall openings as width × height, and ceiling openings as width × length.

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
Measure the inside duct opening edge to edge: 4 inches wide and 10 inches long
Example shown: a 4 inch × 10 inch inside duct opening.

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. Record the dimensions in the format shown for floor, wall or ceiling openings.

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 × Length

Measure the inside width across the ceiling opening, then measure the inside length from end to end.

Record asWidth × Length
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.

  1. 1

    Remove the existing cover

    Expose the actual duct opening. Do not measure across the face, flange or outside perimeter of the old cover.

  2. 2

    Measure the inside width

    Place the tape at one inside edge of the duct and measure straight across to the opposite inside edge.

  3. 3

    Measure the second dimension

    For floor and ceiling openings, measure the inside length. For wall openings, measure the inside height.

  4. 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 Sizes

Avoid 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.

Request a Custom Size Ask a Measurement Question

Measurement Questions

Questions before you order.

Is vent size based on the duct opening or the outside dimensions?

Use the inside duct-opening dimensions. Remove the existing cover or register and measure from one inside edge of the opening to the opposite inside edge.

How do I measure a floor vent cover or floor register?

Measure the inside width × length of the floor duct opening. Keep any fractions and compare that measurement with the listed Airwinks size.

How do I measure a wall vent cover?

Measure the inside width from side to side, then the inside height from top to bottom. Record the wall opening as width × height.

How do I measure a ceiling vent cover?

Measure the inside width across the ceiling opening, then the inside length from end to end. Record the ceiling opening as width × length.

What if my opening does not match a listed Airwinks size?

Submit the exact inside-opening dimensions and installation details on the Custom Vent Covers page for review.

Should I measure every vent opening separately?

Yes. Openings that look alike can still differ. Remove each existing cover and verify the inside opening before ordering.

Ready to Shop?

Choose the installation surface.

Floor Vent Covers & RegistersShop by duct-opening size → Wall Vent CoversShop by duct-opening size → Ceiling Vent CoversShop by duct-opening size →