What Size Vanity Unit Works in Your Bathroom?

A vanity unit that looks right on a product page can quickly feel oversized once the bathroom door, shower screen and daily routine come into play. If you are asking what size vanity unit to buy, the answer is not simply the widest model that will fit between two walls. It is about choosing enough basin and storage space while keeping the room comfortable to move around and easy to clean.

For most bathroom projects, start with the available floor area, then work back from the clearances you need around the unit. This approach helps homeowners avoid a cramped layout and gives fitters a clearer installation plan before tiles, pipework and furniture are fixed in place.

Start with the bathroom layout, not the unit

Measure the wall where the vanity will sit, but do not stop there. Record the full width, the depth from wall to opposite obstruction, and the location of the door swing, radiator, toilet, bath, shower tray and any existing soil pipe boxing. Measure at skirting level as well as at worktop height, particularly in older properties where walls are not always straight.

A vanity unit needs usable space in front of it. As a working guide, aim for around 700mm of clear floor space from the front of the unit to the nearest opposing fixture or wall. A little less can work in a compact cloakroom, but it may feel restrictive if drawers need to open or more than one person uses the room.

Door clearance matters just as much. Check whether the bathroom door opens into the room and whether it could hit the vanity or block access to the basin. In tight spaces, an outward-opening door, pocket door or a shallower unit can make a major difference, subject to your layout and building requirements.

What size vanity unit is right for each bathroom?

Vanity units are commonly available from compact 400mm options through to double-basin furniture at 1200mm and beyond. The right width depends on the room, how the bathroom is used and the storage you genuinely need.

Cloakrooms and en-suites: 400mm to 600mm

A 400mm or 500mm vanity unit is often the practical choice for a downstairs cloakroom or small en-suite. These sizes provide a handwashing basin and some concealed storage without taking over the room. Corner units can also be useful where a standard rectangular unit would interfere with the door or toilet.

At this scale, depth is often the deciding measurement. A slimline vanity, typically around 200mm to 380mm deep, preserves valuable circulation space. The trade-off is a smaller basin and reduced drawer capacity, so choose a compact bottle trap and plan carefully for cleaning products or spare toilet rolls elsewhere.

A 600mm unit is a popular step up where the wall allows it. It gives a more comfortable basin for everyday use and often provides meaningful cupboard or drawer storage, while still suiting many smaller family bathrooms.

Main bathrooms: 600mm to 800mm

For a typical UK main bathroom, a vanity unit between 600mm and 800mm wide is usually a well-balanced option. It offers a basin that is practical for washing, shaving and children’s routines, plus storage for toiletries that would otherwise sit around the room.

A 600mm vanity can be enough in a compact bathroom, especially if a separate tall cabinet or mirrored cabinet is included. Choose 800mm where the layout has the space and you want wider drawers, more worktop area around the basin, or a stronger furniture-led look.

Do not assume a larger unit automatically creates a better result. An 800mm model in a narrow room can leave too little room beside a toilet or make access to the bath awkward. The finished bathroom should feel considered, not filled wall to wall.

Larger bathrooms: 900mm to 1200mm and above

A 900mm or 1000mm vanity unit suits a generous family bathroom where storage is a priority. These widths work particularly well with wide single basins, creating useful surface space on both sides for soap dispensers and everyday items.

For a shared bathroom, 1200mm furniture with double basins can reduce the morning queue. However, two basins require more than additional width. You need suitable hot and cold feeds, waste positions, enough room for two users to stand comfortably, and storage that remains practical once the plumbing is in place.

A double vanity is most effective when it supports the way the household actually uses the bathroom. In some homes, one large basin with deep drawers is more useful than two smaller bowls and limited storage.

Check depth before committing

Width gets most of the attention, but vanity unit depth can decide whether the layout works. Standard units are often around 450mm to 500mm deep. This provides a generous basin and better storage, making it a sensible choice where the room has enough projection space.

Slimline units are typically shallower and are designed for narrow bathrooms, cloakrooms and en-suites. They can transform a difficult layout, but check the basin projection rather than relying on the cabinet measurement alone. A countertop basin or curved front can extend further into the room than expected.

Allow for the finished wall surface when measuring. If tiles are still to be installed, include the tile thickness, adhesive bed and any wall levelling work. It may only add a small amount, but tight installations leave little tolerance for surprises.

Choose wall-hung or floorstanding with the room in mind

Wall-hung vanity units create visible floor space beneath the cabinet, which can make a smaller room appear more open. They are also easier to clean under and allow the fitting height to be tailored to the household. A typical basin height is around 800mm to 850mm from the finished floor, though this can vary with the basin and user needs.

They do require a sound fixing surface. Stud walls may need noggins or additional reinforcement, and plasterboard alone is not enough for a heavy unit loaded with products. Plan the support before boarding the wall if possible.

Floorstanding vanity units can be more forgiving in refurbishment work, particularly where wall structure is uncertain or existing pipework comes up through the floor. They offer a grounded, furniture-style finish, although plinths, legs and tight side gaps need consideration when cleaning.

Plan storage around plumbing

A vanity unit is often chosen to hide pipework, but plumbing can reduce the storage you expected to gain. Drawer units may have shaped internal sections to accommodate the trap and wastes. This is normal, but compare the usable drawer layout rather than judging the cabinet by its external size.

If the waste pipe enters through the back wall, fitting is often neater and more flexible. Floor wastes and bulky valves can take up room inside the cabinet, especially on slimline furniture. Discuss the proposed unit with your installer before first-fix plumbing is finalised.

Also consider the opening style. Doors need clear room to swing, while drawers pull directly into the floor space in front. Soft-close drawers are excellent for organised storage, but only if they can open fully without colliding with a toilet, bath panel or heated towel rail.

Match the basin, tap and mirror proportions

The vanity and basin should read as one balanced element. With a countertop basin, check the combined height of unit and bowl so the rim does not become uncomfortably high. With an inset basin, confirm the tap-hole position and whether the chosen tap needs a basin-mounted or wall-mounted installation.

The mirror or mirrored cabinet above should generally sit within the visual width of the vanity. It does not have to match exactly, but a very narrow mirror above a wide unit can look disconnected. Leave enough space above the tap and basin for comfortable cleaning and for any splashback tiles or decorative wall finish.

A final measuring check before ordering

Before you order, mark the vanity footprint on the floor with masking tape or cardboard. Open the door, stand at the marked basin position, and mimic opening drawers. This simple check reveals pinch points that a written measurement can miss.

Record the unit width, total depth, basin projection, door or drawer opening space, pipe locations and finished wall dimensions. If your plan includes new wall or floor tiles, account for their build-up before fixing furniture positions.

The best vanity unit size is the one that gives your bathroom proper function as well as a polished finish. Choose the proportions that suit the room, plan the installation details early, and you will have storage, comfort and a bathroom layout that works every day.