Replace a Bathroom Vanity: Measure, Fit and Budget

Start with the decision you are actually making

Imagine that your bathroom still functions, but the existing vanity is swollen at the base and its drawers stick. You are not planning a full renovation. You would like a better-looking cabinet, a basin that is easy to clean and perhaps more storage. It is tempting to shop by color and advertised width first. Yet a vanity is one of the few pieces of furniture that has to fit the room, the moving doors, the drain and the water supplies simultaneously. Finding a cabinet that satisfies only three of those four conditions can turn a modest refresh into a plumbing project.

Decide at the outset whether you want to preserve the existing plumbing positions. A same-location swap usually has a simpler scope than moving the sink across a wall, but “same location” does not automatically mean “no plumbing work.” The new cabinet may have drawer boxes or a center divider where the old open cabinet had empty space. Its basin drain may sit several inches away from the current connection. The safe purchasing question is therefore: Will this particular cabinet and basin fit my measured room and my actual pipe arrangement?

Use a small written brief: preferred style, maximum total width, maximum projection from the wall, comfortable working height, storage must-haves, and whether the new installation must use the current drain and supply locations. This gives you a standard for saying no to a beautiful product that would require a different project.

Measure the room, not just the old cabinet

Make a top-down sketch before opening a shopping site. Record the clear wall width where the vanity will stand, including any sloping walls, exposed baseboards or adjacent trim. Measure from the finished wall to the nearest point a new vanity or countertop may project into the room. Then open the bathroom door fully, open the shower enclosure if there is one, and note the path of drawers and cabinet doors. The cabinet may fit while its door hits the toilet or while a drawer blocks the room's only comfortable standing area.

Measure the existing cabinet width, depth and height, but also the countertop separately. A top can overhang the cabinet on one or both sides. For example, if the current base is 36 inches wide and its top is 37 inches wide, copying only the base measurement leaves out an important inch. A replacement kit's listed dimensions may describe the base, the top or an assembled product; read the specific manufacturer's dimension drawing instead of assuming every “36-inch vanity” occupies exactly 36 inches.

For a fictional example, suppose the unobstructed wall width is 40 inches. A 36-inch base with a verified 37-inch top leaves 3 inches in the width calculation. That is not a promise that it will install with 1.5 inches on each side. Wall irregularities, top placement, wall trim, exposed edges and manufacturer's required clearances may use some of that space. Put the actual left and right gaps on your sketch and check the product drawing before buying.

The Home Depot vanity measurement guide distinguishes cabinet dimensions from countertop overhang and emphasizes door swing and plumbing placement. The Lowe's vanity selection guide also asks homeowners to account for doors, drawers and trim. Those are useful checks, but your exact model's installation instructions take precedence over a typical-size chart.

Look inside before choosing drawers and shelves

Open the existing vanity and take photographs of the drain pipe, trap and water supply shutoffs. Measure the center of the drain and the two supply positions from a fixed wall or corner, and record their heights above the finished floor. Do not rely on a picture with no ruler in frame. Sketch where each pipe enters the wall or floor. That information tells you whether a shelf, U-shaped drawer cutout, rear panel or sink bowl may interfere with the installation.

Pay special attention to cabinet designs with full-depth drawers beneath the sink. They can look wonderfully organized in a showroom, yet the space behind each drawer is not always available for a waste connection. A model with an open plumbing chase may be the better fit. Conversely, a cabinet that fits the pipework can still have a basin whose drain is in the wrong place. Check the base cabinet and basin together; do not assume a top sold separately will match the plumbing arrangement.

Inspect accessible areas for water damage and note dampness or staining around shutoffs, flooring and wall penetrations. If valves do not operate properly, or you see signs of active leakage, have a qualified professional assess the problem before committing to a cosmetic swap. Do not conceal damage behind a new cabinet simply because it will no longer be visible. Plumbing alterations, disconnection and reconnection, applicable permits and safe testing depend on local requirements and the actual installation. This guide is for planning and quote comparison, not a procedure for modifying pipework.

Choose the complete assembly, not a picture of the cabinet

Online listings are inconsistent about what “vanity” includes. One price may cover only the cabinet; another may include a top, integrated basin, backsplash and handles. A third might include a faucet in the photograph but not in the box. Before comparing advertised prices, write out what you receive: cabinet, top, sink, faucet, drain assembly, handles, mirror, side splash, backsplash and mounting hardware. Label each part included, optional or purchased separately.

Then read the dimensions of the entire assembled product. A sink can be centered or offset, and a countertop edge can project farther than its cabinet. Confirm the faucet hole configuration against the faucet you plan to reuse or buy. Check how the top is supported, especially with wall-mounted or floating styles; those may need professional assessment of the wall structure and fixing method. Do not infer load capacity from a photograph.

Think about daily maintenance as well as appearance. A shallow basin may splash more in a high-use family bathroom. An open shelf may look attractive but expose stored items to humidity and dust. A high-gloss finish may display water spots; a deep cabinet may reduce comfortable floor space. These are personal trade-offs, not universal rankings. If the bathroom is shared by children and adults, the comfortable basin height and accessible storage may matter more than an extra decorative drawer.

Build a realistic example budget

Consider this fictional six-line estimate in US dollars. It is a demonstration of how to organize costs, not a current regional price guide or a contractor quote. A cabinet is budgeted at $320, the basin and top at $210, a faucet at $95, fittings and valves at $40, removal and disposal at $30, and a professional plumbing connection and leak check at $210. The itemized subtotal is $320 + $210 + $95 + $40 + $30 + $210 = $905.

If this particular homeowner sets aside a planning contingency of 15% of the subtotal, that adds $135.75 and produces a working allowance of $1,040.75, before any unquoted taxes or concealed repair work. That calculation is not a prediction that hidden issues will cost 15%. It is merely a deliberate buffer that keeps the owner from spending the entire available amount on the cabinet itself.

Now imagine the winning product needs a relocated drain or the existing floor was installed only up to the old cabinet. Those changes are not accounted for by multiplying the vanity price by a generic markup. Ask for a separate written scope and updated quote. This is why buying a slightly less expensive cabinet can end up costing more if its fit creates additional trades or replacement flooring. Use the Bathroom Remodel Cost Calculator to explore the broader bathroom budget and the Project Budget Workspace to record actual supplier and contractor line items. Replace sample values with your own figures.

Compare two offers on the same scope

A common comparison is a low online cabinet-only price against a higher local offer that includes delivery, the top and installation. They are not equivalent. Ask both sellers or installers the same questions: Is the basin supplied? Who removes the old vanity? Who disposes of it? Who reconnects the water and waste lines? Are old valves included if replacement is required? Is the countertop measured and fitted on site? Who repairs the wall or floor if removal reveals a gap? What is the warranty responsibility if a leak appears after installation?

Write exclusions beside inclusions. If one quotation says “installation included” but says nothing about plumbing, do not assume plumbing is covered. The Federal Trade Commission's home-improvement guidance stresses written estimates and clear contracts. Keep payment stages, changes to the scope and agreed finishes in writing, and check local contractor requirements rather than making decisions from a verbal reassurance.

Delivery and returns deserve a line too. A countertop damaged in transport or a cabinet ordered to the wrong depth can ruin a weekend schedule. Inspect the manufacturer's return conditions and lead times before making a purchase that cannot easily be reversed. If your chosen model has a longer delivery date, schedule any authorized removal only after you have confirmed the replacement and the installer are actually available.

A measurement and leak-risk handoff card for the installer

Before paying a deposit, put all measurements on one page using a consistent reference: finished floor for vertical heights and the same finished side wall for horizontal distances. Give the installer the manufacturer drawing, not only an advertised cabinet width. A common mistake is to measure the old cabinet's exterior while ignoring the basin lip, countertop overhang, trim interference or offset internal supports in the replacement.

Ask the installer to confirm the chosen assembly on site before irreversible cuts or plumbing changes. If the baseboard or floor beneath the old vanity is stained or soft, do not cover the damage with a new cabinet. Document and address the moisture source first. After connection, a responsible installer should test hot and cold supplies and the drain, including a filled-basin drain cycle where appropriate, and inspect for leaks before the cabinet is considered ready. Local plumbing rules and the fixture manufacturer's instructions take precedence over this homeowner record.

This checklist is for communication and purchase decisions, not instructions to alter supply or waste piping without the proper qualifications. It helps the homeowner pay for a functioning installation rather than merely a cabinet that fits in a product photograph.

Plan the order of work without rushing

A homeowner can prepare the project responsibly without performing plumbing work. First, measure and photograph the room. Next, choose a product whose dimension drawing matches the available space. Confirm pipe locations and agree which parts of the job require a licensed professional or permits. Obtain itemized quotes for product, delivery, removal, connection and any anticipated finish repairs. Confirm the new pieces are complete and undamaged. Only then schedule removal and installation with the responsible trades.

Keep the old space usable until the project is ready. A second household bathroom may make a delayed installation inconvenient rather than critical; a one-bathroom home has a different tolerance for downtime. Plan for that difference instead of relying on a “one-hour refresh” video. Do not assume a newly installed sink is ready for unrestricted use until the responsible installer has tested connections and any required sealants have met their stated cure conditions.

Finally, photograph the finished connections and save the exact product details and warranties. If the bathroom floor or wall is later changed, you will know the installed vanity's actual dimensions and how it was attached. That modest record can prevent another round of guesswork at the next refresh.

A short buying checklist to take into the store

• Measured clear wall width, available projection and completed door-swing sketch.
• Cabinet, finished countertop and overall assembly dimensions checked separately.
• Drain, trap and supply locations recorded with photographs and a fixed reference.
• Sink and faucet configuration verified against the chosen product.
• Included items, delivery, removal, installation, plumbing and finish repairs listed explicitly.
• Hidden damage, permits, leak testing and any changes in scope allocated to a responsible professional.
• Budget based on complete written costs, with a separate allowance for uncertainty.

The goal is not a perfect diagram or a professional-level plumbing drawing. It is a purchase that fits a real room and a budget that includes the work around the product. A useful bathroom upgrade should feel easier to live with after the installation, not just look better in the shopping cart.