Choose a 400mm vanity when wall space is tight, a 450mm vanity for a little more benchtop and storage without a big footprint jump, or a 600mm vanity when your bathroom has room to spare. The right small vanity unit depends on usable wall width, depth clearance, basin needs and existing plumbing, not just the nominal size.
You've measured the wall. You've stared at the old vanity wondering if 50mm either way really matters. Most people assume the smallest unit is the safest choice, then find out too late that it barely fits a basin they like.
The real question isn't which number sounds the smallest. It's which width, paired with the right depth, basin and storage, works in your space. Once you know that, choosing between 400mm, 450mm and 600mm gets a lot easier.
This guide compares our 400mm vs 450mm vs 600mm Small Vanity Units side by side, then walks through when each size makes sense.
Don't default to the smallest vanity just because your bathroom is compact. If you're still weighing up what size small vanity should you buy, the short answer is that it depends on more than millimetres. A 400mm unit saves wall space, but a 450mm or 600mm option might suit your basin and storage needs better. We'll compare footprint, usability and fit across all three small vanity sizes so you can match the size to your actual layout, not just your room label.
400mm vs 450mm vs 600mm Vanity: Quick Comparison
Here's a quick side-by-side comparison across all three sizes before we go section by section. For a wider shortlist beyond just these three widths, see our best small vanity units for small bathrooms roundup.
400mm Vanity: Most Compact of the Three
The 400mm vanity is best for wall widths under about 450mm, or a powder room where floor space matters more than storage.
450mm Vanity: A Step Up in Width
A middle ground: the 450mm vanity gives roughly 50mm more bench and storage than 400mm, without needing a full 600mm wall run.
600mm Vanity: More Cabinet and Basin Space
The 600mm vanity is best when your wall space allows it and you want more storage or a wider basin without moving up to a full-size vanity.
When Should You Choose a 400mm Vanity?
A 400mm vanity is worth shortlisting when your wall width, room layout or projection space is genuinely limited. If your space is more powder room than full ensuite, our picks for small vanity units for powder rooms narrow things down further, but it comes with a few things to check first.
Consider 400mm When Wall Space Is Limited
If a larger vanity simply won't fit your measured wall, 400mm becomes a realistic shortlist option rather than a compromise.
Check Basin Usability at 400mm
A compact cabinet still needs a basin that works for how you actually use the space. At 400mm, manufacturers usually narrow the basin bowl itself to leave room for tapware and cabinet framing, so the width drop affects hand-washing space more than a wider vanity would. Check the basin size and shape before ordering, not just the cabinet width.
Check Storage at 400mm
Narrower cabinetry can mean less internal storage, but this varies by product. The plumbing trap and waste pipe take up roughly the same amount of internal space whatever the cabinet width, so in a 400mm unit that fixed footprint eats a much bigger share of the usable storage than it would in a 600mm one. Always check the specific configuration rather than assuming.
Recommended 400mm Small Vanity Unit
The Otti Mini Ensuite Fluted Vanity 400mm in Woodland Oak is a solid example of a genuine 400mm unit. It comes in a fluted design and a Woodland Oak finish.
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Width: 400mm
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Design: Fluted front
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Finish: Woodland Oak
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Basin: Above-counter ceramic basin, gloss white, single taphole at 12 o'clock, available in left- or right-hand orientation
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Configuration: 1-door cabinet, opens right to left
The Woodland Oak finish is currently on pre-order, and mirror, tapware and pop-up waste are sold separately. Check the current dimensions, plumbing compatibility and stock availability on the product page before ordering.
When Should You Choose a 450mm Vanity?
A 450mm vanity suits shoppers who want a bit more width than 400mm without moving up to a full 600mm footprint. For more on how to choose the right mini ensuite vanity, compare it directly against 400mm rather than judging it on its own.
450mm vs 400mm: What Changes?
The 50mm difference sounds small, and whether it matters depends on where that extra width goes: some models put it entirely into a wider basin and benchtop, while others use it for thicker side panels or cabinet framing that adds no usable space at all. Actual depth, basin size and internal configuration still need checking product by product.
Check Whether the Extra Width Improves Functionality
Before paying for a 450mm unit, confirm it actually gives you more usable basin or storage space compared with a 400mm alternative, not just a wider overall footprint. Some do. Some don't; it comes down to whether the manufacturer put the extra 50mm into the interior or into the cabinet frame.
Recommended 450mm Wall-Hung Vanity
The ABS Vienna Mini Wall Hung Vanity 450 in Solid Timber is a concrete 450mm comparison point. It's a wall-hung design finished in solid timber.
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Width: 450mm
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Configuration: Wall-hung, one door
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Basin: Single bowl, poly marble top
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Finish: Solid Timber with a fluted panel and durable PVC coating
A wall-hung vanity carries its full weight through the wall bracket, so confirm the wall behind it is timber or steel stud, not just plasterboard, along with exact dimensions and plumbing compatibility, before you buy.
When Should You Choose a 600mm Vanity?
Move up to 600mm when your available wall space genuinely allows it. Extra width only helps if it adds real function, so don't assume bigger automatically means better.
600mm vs 450mm: Consider the Extra Width
Check whether your room can accommodate the additional width while still leaving enough clearance to move around comfortably.
Consider Basin and Benchtop Requirements
More width can mean a larger basin or extra benchtop, though this depends entirely on which model you pick.
Consider Your Storage Requirements
A wider vanity doesn't automatically mean more usable storage. Compare actual internal capacity, not just the external footprint.
Recommended Small Vanity with Multiple Size Options
The Timberline ENSUITE Single Bowl Floor Standing Vanity comes in 460mm, 600mm and 750mm, so you can pick the 600mm option and keep the same cabinet design. The 460mm and 600mm widths are fitted with two doors, while only the 750mm model steps up to two drawers and a door. It's made to order in any woodgrain or painted finish.
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Width: 600mm (also available in 460mm and 750mm)
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Configuration: Floor standing, two doors (460mm and 600mm) or two drawers and a door (750mm)
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Basin: Single bowl
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Finish: Any woodgrain or painted finish, made to order (around 2–3 weeks production)
It's made to order in Australia with roughly 2–3 weeks production time, so confirm your chosen finish and basin details on the product page before ordering.
Does Vanity Depth Matter as Much as Width?
Comparing only width across 400mm, 450mm and 600mm isn't enough. Getting this right comes down to knowing how to measure your bathroom before buying a small vanity unit, not just comparing width. Depth, or projection, can affect circulation and fixture clearance just as much in a small bathroom.
Compare Width and Depth Together
Always check both measurements against your usable installation area, not width alone.
Allow Enough Clearance Around the Vanity
Account for doors, shower screens, drawer swing and the toilet, since the ABCB Livable Housing Design Standard (updated to version 1.3 in November 2023) requires any fixed obstruction, including a basin or vanity unit, to sit at least 450mm from the toilet pan's centreline.
Does Wall-Hung vs Freestanding Affect the Size You Should Choose?
Installation style is a separate decision from nominal width. A wall-hung vanity leaves the floor visible underneath, which can make a small bathroom feel more open and makes cleaning the floor easier, but it needs the solid wall support covered earlier. A freestanding vanity sits directly on the floor, which is usually simpler to install and doesn't depend on wall type, but takes up visible floor space right down to the skirting. Weighing up wall-hung vs freestanding small vanity units in more depth means comparing actual dimensions rather than assuming one type suits small spaces better by default.
How Basin Configuration Changes the Size Decision
Basin type matters as much as vanity width. An integrated basin is moulded flush into the benchtop, which keeps the surface easy to wipe down and suits a narrower 400mm unit where every millimetre of bench counts. An above-counter basin sits proud of the top, which usually needs a taller tap and adds visual height, but can free up a touch more depth underneath for storage on a 450mm or 600mm unit. Comparing integrated vs above-counter basins for small vanity units in more depth shows how tap positioning and benchtop space change with each, so factor this into your size decision, not just the cabinet dimensions.
How Storage Changes the Size Decision
External width doesn't tell the full storage story. Drawers generally give you better organised, easier-to-reach storage than a single cabinet door, but the plumbing trap running down the centre of most vanities forces a split or half-depth drawer either side of it, so a two-drawer spec doesn't always mean two full-depth drawers. Weighing up drawers vs cabinets for small vanity units comes down to drawer layout, cabinet depth, basin position and plumbing space, all of which affect how much you can use inside.
Check Plumbing Before Changing Vanity Size
To choose a small vanity unit that fits your existing plumbing, start by checking your existing water and waste positions. Northern Territory Government guidance notes that altering water supply or waste plumbing generally calls for a licensed plumber, so check this before you commit to a size that won't line up.
Check Existing Water and Waste Positions
Identify where your current waste and water points sit before choosing a replacement with different dimensions.
Check Internal Plumbing Space
Plumbing can eat into internal cabinet space regardless of a vanity's nominal width. Any new tapware or fittings also need WaterMark certification to be legally installed, so check this against the product's internal layout and specs.
Frequently Asked Questions
Will a 750mm vanity fit if my wall is 850mm wide?
Not necessarily. Usable wall width, side clearance, vanity depth, nearby doors and fixtures, and plumbing all affect real fit, so measure beyond the raw 850mm before confirming. If your numbers do work, the Timberline ENSUITE range covered above also comes in 750mm.
Which 750mm vanities have drawers without plumbing taking up most of the storage?
Compare the drawer cut-out, basin waste position and service entry point on the product diagrams before ordering, since plumbing placement varies by model.
400mm vs 450mm vs 600mm Vanity Buying Checklist
Run through this before you order:
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Measure your available width and depth, not just the old vanity's size
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Check clearance around doors, fixtures and drawers
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Narrow down a size range based on your usable space
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Compare basin configuration options for that size
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Assess actual internal storage, not just external width
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Decide between wall-hung and freestanding
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Check existing plumbing positions
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Verify exact product dimensions before ordering
Shop Small Vanity Units by Size
Once you know your size range and configuration, it's easier to compare real options side by side. We stock 400mm, 450mm and 600mm vanities across a range of finishes (plus 750mm in select ranges like the Timberline), with Australia-wide delivery. Shop any 400mm or 450mm or 600mm Small Vanity Units at Zure and check individual product specs before you order.