Bathroom Vanity Size Calculator
A vanity unit that is too wide for the wall will crowd nearby fittings or block a door, while one that is too narrow leaves usable space wasted. Enter your available wall width below to get a recommended vanity unit size.
Work out the largest vanity unit that will fit
Enter the available wall width to get a recommended vanity unit size.
Leaving 15cm clear for pipework, door swing and adjacent fittings, the largest vanity unit you should fit is:
60cm wide
This is a standard vanity unit width, so it should be easy to source.
Recommended products
A few well-reviewed vanity units at a range of widths.
£94.49
Pros
- Includes slim-edge ceramic wash basin
- 2-door storage cabinet
- Gloss white finish
Cons
- Flat-pack — self-assembly required
- Basin tap sold separately
- Gloss Laminate
- White
£234.97
Pros
- Wall-hung design makes cleaning easy
- Soft-close drawers
- White glass basin included
- 900mm width suits most UK bathrooms
Cons
- Requires stud wall fixings for wall-hung install
- PVC-Wrapped Chipboard
- White
£169.99
Pros
- Compact 500mm option for small bathrooms
- 2-drawer storage
- White finish suits most décor
Cons
- Basin tap and waste typically sold separately
Frequently asked questions
How much clearance should I leave around a bathroom vanity unit?
It is sensible to leave around 15cm of total clearance along the wall for pipework, a door swing, or an adjacent toilet or bath, rather than fitting a vanity right up to the edges of the available space.
Why should I round down to a standard vanity size instead of a custom width?
Standard widths such as 40, 50, 60, 80, 100 and 120cm are far easier to find in stock and usually cheaper than a bespoke unit, so rounding down to the nearest standard size keeps your options wide and your budget lower.
What if my wall is narrower than 40cm?
In a very tight space, look at wall-hung basins or corner vanity units instead, since most freestanding or floor-standing vanity ranges start at around 40cm wide.
Does the vanity width need to match the mirror above it?
Not exactly — a mirror that is roughly the same width as the vanity, or a touch narrower, generally looks best, so it is worth checking our bathroom mirror size calculator once you have settled on a vanity width.
How this calculator works
The calculator takes your available wall width and subtracts a 15cm clearance allowance. This clearance is for pipework access, door swing, and any adjacent fittings like a toilet, bath or shower. The result is the maximum vanity width that will fit. The calculator then rounds down to the nearest standard vanity width from the range of 40, 50, 60, 80, 100 and 120cm.
Standard widths are used because they're far easier to find in stock and usually cheaper than bespoke units. A 15cm clearance is a minimum — if you have more space, you can choose a smaller vanity for aesthetic reasons or to leave room for a wall cabinet, shelves or plants. If your wall is narrower than 40cm, most standard vanity ranges won't fit, and you should look at wall-hung basins or corner vanity units instead.
Standard UK bathroom vanity widths
| Vanity width | Minimum wall width (with clearance) | Typical use | Room type |
|---|---|---|---|
| 40cm | 55cm | Cloakroom, small ensuite | Very small bathroom |
| 50cm | 65cm | Compact bathroom | Small bathroom, guest WC |
| 60cm | 75cm | Standard bathroom | Family bathroom, standard ensuite |
| 80cm | 95cm | Large bathroom | Master bathroom, main bathroom |
| 100cm | 115cm | Spacious bathroom | Large ensuite, master bathroom |
| 120cm | 135cm | Very large bathroom | Open-plan, luxury ensuite |
Worked example: A 105cm wide wall
A wall 105cm wide with 15cm clearance gives a maximum vanity width of 105 - 15 = 90cm. The calculator rounds down to the nearest standard width, which is 80cm. This leaves 10cm of extra clearance on one side, which is useful for pipework access and makes the vanity look less cramped against the wall.
If you had a 120cm wall, the maximum vanity width would be 120 - 15 = 105cm, rounding down to 100cm. A 100cm vanity gives a substantial storage and basin area for a master bathroom, with 5cm of clearance on each side. If you need more than one basin, a 120cm vanity with two basins is an option, but you'd need at least 135cm of wall width to fit it comfortably.
Common mistakes when choosing a vanity size
- Fitting the vanity right up to the edges of the wall with no clearance. A 15cm clearance is a minimum for pipework access and door swing — without it, you won't be able to reach the taps or waste pipes for maintenance, and the vanity door (if it has one) may hit the wall or a nearby fitting.
- Forgetting to account for the toilet or bath. If the vanity is next to a toilet, the toilet cistern and lid need clearance too — typically 20-30cm in front of the cistern. If the vanity is next to a bath or shower, make sure the door or curtain can open and close without hitting the vanity.
- Choosing a vanity that's too wide for the room's proportions. A 120cm vanity in a 140cm-wide bathroom leaves only 10cm on each side, which can feel cramped and unbalanced. Sometimes a smaller vanity with better proportions and more open space creates a more luxurious feel than a maximum-width unit.
- Not checking the door swing. If the bathroom door opens inward, make sure the vanity doesn't block it. A common mistake is fitting a large vanity that leaves the door able to open only 45 degrees, making the bathroom feel awkward to enter and exit.
What to look for when buying a bathroom vanity
Vanity type affects both the footprint and the storage. A floor-standing vanity with legs or a plinth is the most common type and gives a traditional look with good storage. A wall-hung vanity is mounted on brackets above the floor, giving a modern look and making the room feel larger by exposing more floor area. A corner vanity fits into a 90-degree corner and is ideal for very small bathrooms where space is at a premium.
Basin type matters for practical use. A countertop basin sits on top of the vanity and gives the most work surface, but it reduces the internal storage height. A semi-recessed basin sits partly into the vanity, giving more internal space while still having a rim. An undermount basin is fixed underneath the vanity top, giving a seamless look with no rim to catch water, but it needs a solid surface like stone or solid surface material.
Finally, think about the taps. A vanity with a single tap hole is simpler to plumb but limits your tap choice. A three-hole tap (hot, cold, and spout) gives more flexibility but needs more precise tap placement. If you want a tall mixer tap, make sure the vanity is deep enough (typically 40-45cm) to accommodate it without the tap overhanging the edge. A wall-mounted tap frees up counter space and makes cleaning easier, but it needs separate plumbing in the wall.
More questions answered
How much clearance should I leave around a bathroom vanity unit?
It is sensible to leave around 15cm of total clearance along the wall for pipework, a door swing, or an adjacent toilet or bath, rather than fitting a vanity right up to the edges of the available space.
Why should I round down to a standard vanity size instead of a custom width?
Standard widths such as 40, 50, 60, 80, 100 and 120cm are far easier to find in stock and usually cheaper than a bespoke unit, so rounding down to the nearest standard size keeps your options wide and your budget lower.
What if my wall is narrower than 40cm?
In a very tight space, look at wall-hung basins or corner vanity units instead, since most freestanding or floor-standing vanity ranges start at around 40cm wide.
Does the vanity width need to match the mirror above it?
Not exactly — a mirror that is roughly the same width as the vanity, or a touch narrower, generally looks best, so it is worth checking our bathroom mirror size calculator once you have settled on a vanity width.
Should I get a vanity with a countertop basin or an undermount basin?
A countertop basin sits on top of the vanity and gives you more work surface for toiletries, but it reduces the internal storage height. An undermount basin is fixed underneath and gives a seamless, easy-to-clean look with no rim to catch water, but it needs a solid surface like stone or solid surface material. For a family bathroom with lots of bottles and tubes, a countertop basin is usually more practical.
What's the difference between a floor-standing and wall-hung vanity?
A floor-standing vanity sits on the floor and gives a traditional look with enclosed storage. It's easier to install and usually cheaper. A wall-hung vanity is mounted on brackets above the floor, giving a modern, floating look that makes the bathroom feel larger and exposes more floor area for cleaning. Wall-hung vanities need a solid wall (usually masonry or reinforced plasterboard) and the plumbing needs to be concealed in the wall.
Do I need a vanity with a cabinet or just a basin?
A vanity with a cabinet gives essential storage for toiletries, cleaning supplies and spare toilet rolls — especially important in a small bathroom where every centimetre counts. If you have plenty of storage elsewhere (a separate wall cabinet, a tall tower unit, or a separate airing cupboard), you can get away with a simple basin on a console or wall bracket, but most bathrooms benefit from the extra storage a cabinet provides.
How deep should a bathroom vanity be?
Standard bathroom vanities are typically 40-45cm deep, which is enough for most basins and gives reasonable internal storage. If you have a very small bathroom, a shallow vanity (35-40cm) can help create more floor space, but it may feel cramped if you're sharing with others. If you have a large bathroom and want a substantial vanity, 50-60cm depth gives more storage and a more substantial look, but make sure it doesn't dominate the room.