6x12 Metal Wall Vents: Free Area, Airflow and Duct Fit
A 6x12 wall vent has a free area of 18.3 square inches and a calculated airflow of 64 CFM, and it drops into a duct opening of 146.1 x 298.5 mm.
- Duct opening
- 5.75″ × 11.75″
- Metric
- 146.1 × 298.5 mm
- Best free area
- 18.3 sq in
- Comes in
- Flush Wall · Framed Wall
6x12 is where the wall line's inner tray steps in rather than tracking the duct, dropping to 117.5 mm from the 6x10's 123.8 mm, and free area jumps 43 percent to 18.3 square inches for two extra inches of length.
Free area and airflow at this size
| Product | Free area | Open | Airflow | Price | |
|---|---|---|---|---|---|
| Flush Wall Vent [Metal] | 18.3 sq in | 25% | ≈ 64 CFM | from $49.99 | View 6x12 |
| Framed Wall Vent [Metal] | 18.3 sq in | 25% | ≈ 64 CFM | from $49.99 | View 6x12 |
Free area is the open cross-section air actually passes through, not the outside of the cover. How we calculate it.
Measuring for this size
The rough opening is 146.1 mm by 298.5 mm, the same width as the 6x10 with 50.8 mm more length, so a 6x10 cut can usually be extended, but the narrower inner tray leaves a wider slot that shows more of the inside of the opening.
Why does the 6x12 jump so far ahead of the 6x10?
Because the inner tray changes. On the 6x10 the tray sits at 123.8 mm with an 11.1 mm slot. On the 6x12 the tray steps in to 117.5 mm and the slot opens to about 14 mm, so free area rises 43 percent, from 12.8 square inches to 18.3, for only two extra inches of length.
Can I extend a 6x10 opening into a 6x12?
Yes. Both are 146.1 mm wide and the 6x12 is 298.5 mm long against the 6x10's 247.7 mm, so you need 50.8 mm more length and no change in width. The wider slot on the 6x12 does show more of the inside of the opening, so tidy the cut edges or choose the Framed version.
Should I take the 6x12 or the 6x14?
The 6x12 at 18.3 square inches and 64 calculated CFM covers most rooms, and the 6x14 adds about 10 percent to reach 20.1 square inches and 70 CFM. They share the same 146.1 mm width, so the choice is 50.8 mm of length. Take the 6x14 only if the framing allows it without heading off a joist.
How do I measure for a replacement vent?
Measure the duct opening, not the old cover. Pull the existing vent out, measure the hole itself across the width and the length in millimetres, and match that to the duct dimension listed on this page. Vent sizes are named for the duct, so a vent called 4x10 has a face larger than 4 by 10 inches. Measuring the faceplate is the single most common reason a size arrives wrong.
What happens if I order the wrong size?
Email support@khansupply.co with your order number and the millimetre measurements of your opening, and we will work out which size actually fits and sort out the exchange. Every Khan Supply vent also carries a 2-year warranty against defects, which is separate from a fit exchange.
What does shipping cost?
Nothing. Shipping is free on every order across North America, on a single vent and on a 5-pack alike. You will get tracking by email once the order is on its way. If a vent arrives damaged, photograph the box and the part and email support@khansupply.co, Monday to Friday 9 to 5 ET, and we reply within one business day.
Every Khan Supply vent is all metal, not plastic, and ships free across North America with a 2-year warranty. If a size is wrong, email support@khansupply.co and we sort out the exchange. Mon-Fri 9-5 ET, one business day reply.
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