How to Choose the Right Bathroom Vanity Size

Most bathroom renovations stall at the same moment: you've picked a vanity you love, measured the wall, and then realized you forgot to account for the door swing, the toilet clearance, or the plumbing stack that's not quite where you expected it. Vanity sizing isn't complicated, but it requires measuring in the right order and knowing which numbers actually matter. This guide walks you through it.

Start With Three Measurements — Not One

Most people measure the wall and stop there. That's how you end up with a vanity that technically fits but blocks the toilet or makes the door unusable. Before you look at a single product, pull out a tape measure and record these three numbers:

• Available wall width: Measure the full wall where the vanity will sit, then subtract any obstructions — door casings, baseboard heaters, light switch plates. Leave at least 2 inches of breathing room on each side.
• Clearance to the toilet: Building code in Ontario requires a minimum of 15 inches from the toilet centerline to any side obstruction. In practice, 18 inches feels comfortable. If your toilet is close to the vanity wall, this number limits your width more than the wall itself does.
• Door swing radius: Open your bathroom door fully and mark where it stops. A vanity that sits inside that arc will either block the door or get dinged every time someone enters the room.

Once you have all three, your usable width is the smallest of those three numbers. That's your real maximum vanity width.

What Actually Fits in Each Standard Vanity Size

Vanity widths are standardized, which makes comparison straightforward once you know your usable width. Here's what each size realistically suits:

• 24-inch vanity: The right call for powder rooms and small ensuite bathrooms. Enough counter space for a soap dispenser and a small cup — not much else. Single undermount sink. Starting at $499, it's also the most budget-friendly entry point. Browse all sizes here.
• 30-inch vanity: The sweet spot for a standard main bathroom. You get a full-size sink with usable counter on one side. Works well when you need to stay under 32 inches total. See 30" vanities.
• 36-inch vanity: Comfortable for one person with real counter space on both sides of the sink. Good for master bathrooms where a double sink isn't necessary but storage matters.
• 42-inch vanity: A practical middle ground — more storage than a 36