Lift out the old register
Remove the existing cover so the full duct opening and surrounding floor are visible.
Measure before ordering
How to measure your floor vent opening.
Remove the old register and measure the clear opening in the floor. Order by the inside width and length of that opening, not by the outside dimensions of the old cover.
The product size refers to the duct opening.A product labelled 4 × 10 is intended for a nominal 4 × 10-inch opening.
Inside width
Inside length
Remove the old registerExpose the actual duct opening
Measure inside edgesDo not include the old flange
Record width and lengthUse the clear opening dimensions
Confirm before checkoutCompare with the listed nominal size
Four measurement steps
Measure the opening, not the decorative cover.
A conventional register normally overlaps the floor, so its outside dimensions are not the size used when ordering a replacement floor-matching vent.
Measure the inside width
Place the tape across the shorter clear inside dimension of the opening.
Measure the inside length
Measure the longer clear inside dimension without including the surrounding floor.
Match the nominal size
Choose the product whose listed opening dimensions match the measurement you recorded.
Record the opening
Write down both clear inside measurements.
Measure carefully and repeat the measurement before ordering. If the opening is irregular, check it at more than one point and correct significant damage or distortion first.
Inside width________ inches
Inside length________ inches
Correct: measure the duct opening
Measure from inside edge to inside edge after the old register has been removed.
Incorrect: measure the old cover
The visible flange is larger than the duct opening and can lead to ordering the wrong size.
Correct: check twice
Repeat both measurements and compare them with the product’s nominal opening size.
Incorrect: guess or round freely
Do not assume a nearby size will fit an opening that does not match the listed dimensions.
Before placing the order
Check the opening and the surrounding floor.
The opening must be clear and the surrounding floor should provide a suitable surface for the frame. Review the product specifications for the flooring insert area and maximum flooring thickness.
Clear the openingRemove debris, loose material and anything that prevents the frame from sitting correctly.
Inspect the floor edgeRepair significant damage around the opening before installation.
Keep a flooring offcutThe matching insert is customer-supplied and should come from the same flooring project.
Review insert thicknessConfirm that the prepared flooring insert stays within the product’s stated thickness limit.
Choose Black or WhiteSelect the frame finish that works best with the surrounding floor and room.
Ask when uncertainContact us before ordering if the opening does not clearly match an available nominal size.
Measurement questions
Get the size right before checkout.
Correct measurement is the most important step when ordering a floor vent cover online.
Do I measure the old vent cover?
No. Remove the old register and measure the clear inside width and length of the duct opening in the floor.
What does a 4 x 10 vent size mean?
It means the product is intended for a nominal 4 x 10-inch duct opening. The outside frame is larger than the opening so it can rest on the surrounding floor.
Which measurement is written first?
Record both the clear inside width and length. Product names use those two nominal opening dimensions, such as 4 x 10 inches.
Should I round my measurement?
Do not assume a different nominal size will fit. Compare your actual clear opening measurement with the listed product size. Contact us if the opening does not match an available size.
Do I need to measure the depth?
The ordering size is based on the opening width and length. You should still inspect the duct and surrounding floor so the installation area is clear and suitable.
Can I measure before removing the existing register?
The most reliable measurement is taken after the old register is removed because decorative flanges can hide the true opening size.
What if the opening is not square?
Measure the opening in more than one place. If the dimensions vary significantly or the opening is damaged, correct the opening before installing a new vent cover.
Measurements recorded?