Standard Vent Cover Sizes: Wall Vent Sizing Chart

Start with the opening, then check the drawing for the exact vent model. Wall vent size names identify the nominal opening they are intended for. They do not tell you the outside frame size, fixing locations or every clearance needed for installation.

Use the Framed Wall Vent for a visible border over a finished surface, or the Flush Wall Vent when you are planning a mud-in finish. Choose your delivery country on the product page to see the sizes currently offered there.

Catalogue size labels by style

Framed Wall Vent	Flush Wall Vent	What to check
3x10, 4x8, 4x10, 4x12	3x10, 4x8, 4x10, 4x12	Actual body clearance and space for the frame or finishing flange
6x10, 6x12, 6x14, 10x10	6x10, 6x12, 6x14, 10x10	The required airflow and mounting support, as well as the dimensions
8x14	8x14.25	These labels differ. Compare each model's drawing; do not assume interchangeability.
10x30	10x30.25	Check the full opening and installation dimensions before selecting a large grille.
14x14 Exhaust	14x14 Exhaust Mount	Dedicated fan-mount applications need a compatibility check, not just a tape measurement.

This is the catalogue range, not a promise that every size is available in every country. Current prices and availability are shown on the product pages.

Compare the 4x10 wall size and 8x14 wall size pages for the dimensions used by each style. The vent size finder can help shortlist other duct-opening sizes; it does not establish exhaust-fan compatibility.

The measurements to send us

The uncovered opening's width and height, measured at more than one point.
The narrowest clear space inside the duct or cavity, including protruding edges.
The available wall space around the opening and the condition of the mounting surface.
A photo showing the opening, and whether it is a supply, return or exhaust-fan application.
For a mud-in installation, the planned wall build-up and finishing stage.

If the opening is between labels, do not automatically size down. Covering the cut edge is only one requirement; secure mounting, body clearance and airflow still need to work. Email the details to support@khansupply.co before ordering.

Size does not identify the job

A large opening is not automatically a suitable return for a particular cover. Match the system's required airflow and access needs as well as its dimensions. A bathroom exhaust fan is a different assembly: verify its housing, attachment, service access and compatibility with the mount. Send the fan model and opening measurements to support@khansupply.co to confirm the correct mount and instructions.

For help choosing the finish and installation method, read flush versus framed wall vents. For the fitting sequence, use the wall-vent installation checklist.