8 Vanity Measurements to Check Before You Order

Before you order a bathroom vanity, measure eight things: wall width at three heights, clearance to the toilet and door, depth and walkway, drain height and position, supply lines, baseboards and nearby fixtures, floor and wall level, and the delivery path. Write everything down using the side wall as your zero point, so you can compare your measurements with the vanity's listed dimensions.

I've seen a vanity fit perfectly between two walls, only for the drain to land right behind a drawer. The cabinet width was fine, but the plumbing needed attention before the vanity could go in. That's why I always ask about the drain before someone orders.

You'll need a tape measure, a level, painter's tape and your phone. Take photos as you go, especially around the plumbing. They're useful when you're comparing vanities or asking us to check the fit.

What you need before you start

• Tape measure: Record every measurement in inches.
• Level: Check the floor and wall before choosing a cabinet.
• Painter's tape: Mark the vanity's footprint on the floor.
• Phone: Photograph the plumbing, outlets and measurements.
• Vanity dimensions: Keep the cabinet and overall measurements from the product listing handy.
• Measuring worksheet: Download our free Vanity Measuring Worksheet to keep your numbers together.

1. Wall width at three heights

Start at the side wall and measure the available width in three places: along the floor, at counter height and near the top of the space. Finished vanity counters are generally 34 to 36 inches high, so use that range for your middle measurement.

Write down all three widths and use the smallest when checking whether a vanity fits. Also note what's on each side: a wall, toilet, tub or open space. A cabinet that fits at the counter might catch on a wall or baseboard lower down.

Remember the countertop overhang. An overhang is the part of the top that extends beyond the cabinet. Our prefab quartz vanity tops extend about 3/4 inch past each side of the cabinet. If you're fitting a vanity between walls, check the overall top width rather than relying on the cabinet width alone.

For example, our Munich 48" cabinet measures 46.85 inches wide, while the overall width with its top is 47.24 inches. Those are different measurements, and the overall width is the one to compare with your available wall space.

2. Toilet, door and tub clearance

Next, check everything around the vanity. Measure from the center of the toilet to the proposed vanity side. Under IRC R307.1 and P2705.1, the toilet or sink centerline must be at least 15 inches from a side wall or vanity side.

Check the open space in front, too. The IRC calls for at least 21 inches clear in front of a toilet or sink to a wall, fixture or door. The Uniform Plumbing Code, which forms the basis of California's plumbing code, calls for 24 inches in front of a toilet. The National Kitchen and Bath Association (NKBA) recommends 30 inches of clear space in front.

Open the bathroom door all the way and check its swing against the proposed vanity. Do the same for any nearby tub access. A vanity can fit along the wall and still get in the way when you need to move around the bathroom.

If you're still deciding which width to buy, our guide to standard vanity sizes covers that decision. Here, we're checking whether your chosen size works in the room.

3. Depth and walkway

Measure outward from the back wall to see how far the vanity will extend into the room. Most freestanding vanities are 21 to 22 inches deep. Floating vanities, which mount to the wall without resting on the floor, are generally 20 inches deep or less.

Use painter's tape to mark the vanity's outline on the floor. Walk around it, open the bathroom door and picture where you'll stand when using the sink.

If the vanity has drawers, check that they can open fully with enough room for you to stand in front. Include the cabinet pulls and countertop when considering the total depth.

Our Lyon 30" vanity, for example, measures 29-1/2 inches wide, 21 inches deep and 36 inches high. Our Munich 48" measures 21.46 inches deep at the cabinet, but 21.7 inches deep overall with its top. Use the overall measurement when marking the floor.

4. Drain height and position

This is one of the measurements I don't want you to skip. A vanity can fit the wall and walkway, but the drain can land directly behind a drawer or cabinet divider.

Measure from the finished floor to the center of the drain opening. Then measure horizontally from your side wall to the drain center. Write down both numbers.

These plumbing locations are called the rough-in, meaning the positions of the pipes and connections before the vanity is installed.

Bathroom vanity drains are commonly 16 to 20 inches above the finished floor. Floating vanities generally need the drain 18 to 22 inches high so the P-trap can fit inside the cabinet. The P-trap is the curved section of drainpipe beneath the sink that holds water to keep sewer gases from entering the room.

Compare your drain position with the vanity's drawer layout and open space inside the cabinet. Don't assume the plumbing will fit just because the vanity is the right width.

If the drain is slightly off-center, an offset P-trap may help. This is a drain connection that allows the pipe to shift sideways. It can accommodate a drain that's 1 to 6 inches off. If the drain is more than 6 inches off or outside the cabinet, the wall may need to be opened to move the plumbing.

Read our plumbing fix guide before deciding how to handle a mismatch.

5. Supply lines and shutoff valves

Now measure the hot and cold water supply lines and their shutoff valves. These are the connections that bring water to the faucet and let you turn it off beneath the sink.

Supply lines are commonly positioned 2 to 3 inches above the drain and about 4 inches to each side of its center. Record their actual heights from the finished floor and their horizontal positions from your side wall.

Take a photo with the tape measure visible. That gives you something to compare with the cabinet's interior, especially if you're looking at a vanity with drawers.

Check that the valves won't interfere with the drawer layout and that you can still reach them once the vanity is installed.

6. Baseboards, outlets, mirror and lights

Baseboards are easy to overlook. Measure their height from the floor and how far they stick out from the wall. A vanity with a full side panel may not sit flush against the wall if the baseboard is in the way.

Next, record the height and position of outlets and switches. Check them against the finished counter height and any backsplash. A backsplash is the raised piece along the back of the countertop that protects the wall from splashes.

Our prefab quartz vanity tops are 22 inches deep and 3/4 inch thick. They come with a 4-3/4 inch backsplash and one side splash, which is a matching piece installed along the side wall. The side splash is also 3/4 inch thick.

Check whether the backsplash or side splash would interfere with an outlet or switch.

Finally, measure the mirror and wall lights, including sconces, which are lights mounted to the wall. If you're moving to a taller 36-inch counter, compare the new counter and backsplash positions with the existing mirror and lighting.

If you're replacing a pedestal sink, our guide to swapping a pedestal sink for a vanity covers that project.

7. Floor level and wall

Place your level on the floor where the vanity will sit. Check it in both directions: from side to side and from front to back. Then check the wall where the cabinet will meet it.

Record any uneven areas. A level floor and wall make it easier to judge how the vanity will sit, especially when the countertop meets a side wall.

For a floating vanity, check the wall support before ordering. These cabinets need to attach securely to studs, which are the structural framing members inside the wall, or blocking, which is extra framing installed to support the cabinet.

A wall-mounted 72-inch cabinet with a stone top and two sinks can exceed 250 pounds. That's why wall support matters. Confirm the mounting requirements and the location of suitable support before installation.

8. The delivery path

One last measurement before ordering: how will the vanity get into the bathroom?

Measure the doorways, hallways and stairs along the delivery path. Compare those measurements with the boxed dimensions of the vanity you're considering. If the box size isn't on the listing, call or email us and we'll look it up before you order.

Vanities with countertops often arrive assembled, so the delivery path matters just as much as the space where the cabinet will sit.

RTA means ready to assemble. These cabinets can ship flat rather than as a completed cabinet. Our Chalk Birch 48 RTA base, for example, measures 48 inches wide, 22 inches deep including the doors, and 34-1/2 inches high, with a 4-1/2 inch toe kick. A toe kick is the recessed space at the bottom of a cabinet that gives your feet room when you stand close to it. This base can ship flat or assembled.

If you're comparing cabinet styles, our freestanding vanity guide explains that option in more detail.

Your measurements, in one table

Keep these numbers together while you compare product listings. Use the same side wall as your starting point for horizontal measurements and the finished floor for vertical measurements.

Measurement	Where to measure from	Write it here
Wall width at floor	Side wall to opposite boundary
Wall width at counter height	Side wall to opposite boundary
Wall width near top	Side wall to opposite boundary
What's on each side	Left and right of proposed vanity
Toilet centerline clearance	Toilet center to proposed vanity side
Door and tub clearance	Proposed vanity edge to nearby fixtures and open door
Available depth	Back wall toward walkway
Clear space in front	Proposed vanity front to nearest obstruction
Drawer opening space	Proposed cabinet front into walkway
Drain height	Finished floor to drain center
Drain horizontal position	Side wall to drain center
Hot supply line	Finished floor and side wall
Cold supply line	Finished floor and side wall
Shutoff valve positions	Finished floor and side wall
Baseboard height and thickness	Floor to top and wall to outer edge
Outlet and switch positions	Finished floor and side wall
Mirror and light positions	Finished floor and side wall
Floor and wall level	Across the vanity installation area
Wall support for floating vanity	Stud or blocking locations
Delivery path	Doorways, hallways and stairs
Selected vanity cabinet dimensions	Product listing
Selected vanity overall dimensions	Product listing including top
Boxed dimensions	Product packaging specifications

You can also use our free worksheet, which includes these measurement fields. Once you've recorded your numbers, compare them with our freestanding vanities and floating vanities.

For contractors and designers

When reviewing a vanity listing, separate the cabinet dimensions from the overall dimensions. Nominal width is the size used in a product name, while the actual listed dimensions tell you how much space the product occupies.

Our Munich 48" is a useful example. Its cabinet measures 46.85 inches wide and 21.46 inches deep. With the top, its overall dimensions are 47.24 inches wide, 21.7 inches deep and 35.86 inches high.

For rough-in planning, check the actual drain and supply positions against the cabinet's interior. Common drain heights are 16 to 20 inches from the finished floor, or 18 to 22 inches for floating vanities. Supply lines are commonly 2 to 3 inches above the drain and about 4 inches to either side of center. These are starting references, so compare them with the selected cabinet and sink layout.

For floating installations, confirm stud or blocking locations before setting the mounting height. Account for the cabinet, top and sink weight when planning the support.

Also check whether the installation calls for scribing. Scribing means marking and trimming a cabinet edge or fitting piece to follow an uneven wall.

Keep the cabinet, countertop, plumbing and delivery measurements on the same worksheet so the installation team can review them before the order is placed.

Frequently asked questions

How much space do I need next to a toilet for a vanity?

Under IRC R307.1 and P2705.1, the toilet centerline must be at least 15 inches from the vanity side. Also check the space in front of the toilet. The IRC requires at least 21 inches clear, while the Uniform Plumbing Code, the basis for California's plumbing code, calls for 24 inches in front of a toilet. The NKBA recommends 30 inches of clear space in front.

How high should the drain be for a bathroom vanity?

Bathroom vanity drains are commonly 16 to 20 inches above the finished floor. Floating vanities generally need a drain height of 18 to 22 inches so the P-trap fits inside the cabinet. Measure the actual drain height and horizontal position, then compare them with the selected vanity's interior and drawer layout.

Should I measure my old vanity or the wall?

Measure the wall and the available space around it. Your old vanity can be a useful reference, but its dimensions won't tell you whether the new countertop overhang, drawer layout or plumbing connections will fit. Take the wall width at three heights and record the drain and supply positions from the same starting points.

Do I need to remove the baseboard before installing a vanity?

That depends on the cabinet and how it meets the wall. A full side panel may not sit flush over an existing baseboard. Measure the baseboard's height and thickness, then check the cabinet design before deciding whether it needs to be removed or accommodated. The usual fixes are cutting the baseboard back where the cabinet sits or notching the side panel so it fits over the trim.

Call 657-279-8130 or visit the KBF showroom in Anaheim, CA. We ship to the lower 48 states.