Standard Floor Vent Sizes (with Drawing)

Floor vent covers are also known as grilles or registers. They are fixed over the end of an air duct opening to regulate ventilation into a room from an HVAC system. They also serve the purpose of hiding an attractive duct and making it more decorative.

Floor vents come in a wide range of standard sizes, as well as various different styles and materials. If you need to install or replace a floor vent, you will need to understand how to measure for one, which we will explain here.

Measuring for a Floor Vent

When you measure up for a new floor vent cover, it is not as simple as just taking note of the dimensions of your existing vent cover. This is because vent covers are not sold according to the size of their surface, but instead, they are sold according to the size of the duct behind them that they are fitted into.

To find out which size of floor vent cover you need, you will need to remove your existing cover and measure the size of the duct or hole in your floor which was beneath the vent cover. For example, if your duct measures 4 inches by 8 inches, then you will need a vent cover which is 4 inches by 8 inches, in spite of the fact that the actual vent cover plate, which you see in your room when it is fitted will be bigger than this. In fact, a duct that measures 4 inches by 8 inches will typically have a floor vent which has a surface area on the floor of 5 and a half inches by a little over 9 inches.

Be sure to always measure the actual duct size beneath your vent cover before purchasing a new one, because as you can see, it would be easy to make the wrong choice if you base your sizing on the front surface of the vent cover’s measurements.

Standard Floor Vent Sizes

Standard Floor Vent Sizes

Floor vents and their corresponding vent covers come in a range of standard sizes. This is because the ductwork itself also comes in standard sizes to make everything easier to coordinate and fit. The most common floor vent sizes for medium-sized rooms such as bedrooms and dinings rooms are 4 inches by 10 inches, 4 inches by 12 inches, 6 inches by 10 inches, and 6 inches by 12 inches.

In smaller rooms like bathrooms and laundry rooms, the vents will usually be smaller, for example, 2 inches by 10 inches, in order to take up less floor space where it is most valuable. The ‘standard’ vent sizes are those which are most commonly found in standard-sized homes; however, a wider range of floor vents are available. These include:

  • 2 inches by 10 inches
  • 2 inches by 12 inches
  • 2 inches by 14 inches
  • 3 inches by 10 inches
  • 3 inches by 12 inches
  • 3 inches by 14 inches
  • 4 inches by 8 inches
  • 4 inches by 10 inches
  • 4 inches by 12 inches
  • 4 inches by 14 inches
  • 6 inches by 10 inches
  • 6 inches by 12 inches
  • 6 inches by 14 inches
  • 6 inches by 30 inches
  • 8 inches by 8 inches
  • 8 inches by 10 inches
  • 8 inches by 12 inches
  • 8 inches by 14 inches

Oversized Vent Sizes

If you have floor vents that exceed 8 inches by 14 inches, then these will be categorized as oversized vents. These are more common in large open plan areas or in some older houses with double-height entryways; you will find an oversized floor vent in the hallway, which can circulate heat around much of the home. Typically oversized vents will not exceed 16 inches by 16 inches, but larger vents are available. Oversized vents will lack adjustable louvers. These types of vents are available in the sizes listed below.

  • 9 inches by 12 inches
  • 10 inches by 10 inches
  • 10 inches by 12 inches
  • 10 inches by 14 inches
  • 10 inches by 16 inches
  • 10 inches by 18 inches
  • 10 inches by 20 inches
  • 10 inches by 24 inches
  • 10 inches by 30 inches
  • 12 inches by 12 inches
  • 12 inches by 14 inches
  • 12 inches by 16 inches
  • 12 inches by 18 inches
  • 12 inches by 20 inches
  • 12 inches by 24 inches
  • 12 inches by 30 inches
  • 12 inches by 36 inches
  • 14 inches by 14 inches
  • 14 inches by 16 inches
  • 14 inches by 18 inches
  • 14 inches by 20 inches
  • 14 inches by 24 inches
  • 14 inches by 30 inches
  • 14 inches by 36 inches
  • 16 inches by 16 inches
  • 16 inches by 20 inches
  • 16 inches by 24 inches
  • 16 inches by 30 inches
  • 18 inches by 18 inches
  • 18 inches by 24 inches
  • 18 inches by 30 inches
  • 20 inches by 20 inches
  • 20 inches by 30 inches
  • 24 inches by 24 inches
  • 24 inches by 30 inches
  • 24 inches by 36 inches
  • 24 inches by 38 inches
  • 24 inches by 40 inches
  • 24 inches by 42 inches
  • 26 inches by 26 inches
  • 26 inches by 30 inches
  • 26 inches by 36 inches
  • 26 inches by 38 inches
  • 26 inches by 40 inches
  • 26 inches by 42 inches
  • 28 inches by 28 inches
  • 28 inches by 30 inches
  • 28 inches by 36 inches
  • 28 inches by 38 inches
  • 28 inches by 40 inches
  • 28 inches by 42 inches
  • 30 inches by 30 inches
  • 30 inches by 36 inches
  • 30 inches by 38 inches
  • 30 inches by 40 inches
  • 30 inches by 42 inches
  • 32 inches by 30 inches
  • 32 inches by 36 inches
  • 32 inches by 38 inches
  • 32 inches by 40 inches
  • 32 inches by 42 inches
  • 34 inches by 34 inches
  • 34 inches by 36 inches
  • 34 inches by 38 inches
  • 34 inches by 40 inches
  • 34 inches by 42 inches
  • 36 inches by 36 inches
  • 36 inches by 38 inches
  • 36 inches by 40 inches
  • 36 inches by 42 inches