Bathroom Cabinets Calculator

Spec'ing a bathroom vanity? This free bathroom cabinets calculator gives DIYers and contractors a complete vanity take-off — vanity cabinet, doors and drawers, soft-close hinges and slides, knobs and pulls, top width and depth, sink cutout per Kohler-style undermount template, faucet hole count, plumbing rough-in heights, optional linen tower, medicine cabinet (recessed or surface-mount), and framed or LED mirror — all from a single bath-type selection.

Powder room, full bathroom, and primary bath are different scopes. Powder rooms run 18–30" vanities with stock cultured-marble combos; full baths center on 30–48" with semi-custom undermount sinks; primary baths run 60–84" double vanities with linen towers and matched medicine cabinets. The calculator pre-populates each bath type with the conventional default and lets you override every input.

Built on ANSI/KCMA A161.1-2017 (same standard as kitchen — vanity cabinets share the certification), NKBA Bath Planning Guidelines (the 27 Guidelines), ICC A117.1-2017 accessibility (lavatory rim 34" max, knee/toe space, mirror height ≤ 40" AFF), IRC 2021 (R307.1 fixture clearances, P2705.1.5 double-sink spacing, R303.3 ventilation, E3901.6 GFCI), and ANSI/BHMA A156.9 hardware grades. Runs in under a minute, no signup.

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Bathroom Cabinets Calculator

Estimate vanity cabinets, doors, drawers, hinges, pulls, top size, sink cutout, plumbing rough-in, linen, medicine cabinet, mirror, and install cost — for powder rooms, full bathrooms, and primary baths.

Bath type

Sets default vanity width, depth, height, and accessory selection. All values are user-overridable below.

Full bathroom: typical width 30″–60″, default depth 21″.

Vanity dimensions

Standard widths in 6" increments. Depth 21" standard for bath; 18" in tight spaces; 24" matches kitchen-depth aesthetic.

Sink and faucet

Drives cabinet height (vessel reduces 4–7"), top cutout, and faucet hole count.

Wondering why a vessel sink needs a shorter cabinet? See the vanity-height diagram

Where do the drain, supplies, and faucet holes land (and why does a double vanity need 60″)? See the rough-in diagram

Construction tier

Drives door style, finish quality, and lead time.

Semi-custom (KraftMaid, Schrock, Fabuwood, Bertch): 4–12 wk · Soft-close standard; many widths in 3" increments; finished plywood interiors.

Linen, medicine cabinet, and mirror

Optional bathroom storage and mirror selection — sized to the wall and stud bay.

Layout and IRC / NKBA clearance check

Optional — flags non-fatal warnings against IRC R307.1 / IPC 405.3.1 and NKBA Bath Planning Guidelines.

Not sure how much clearance code wants around the vanity and toilet? See the clearance diagram

Plumbing and removal

Existing plumbing accommodation, old vanity disposal, and floating-mount blocking.

How a vanity take-off actually works

Three things trip homeowners up when planning a bathroom vanity, and none of them is the cabinet width. These engineering-style diagrams show the clearances code wants around the vanity, why the cabinet height changes with the sink type (a vessel bowl ships a shorter box), and where the plumbing rough-in lands — including why a double vanity needs at least 60″.

The vanity-clearance plan is why the calculator checks the room around the cabinet, not just the cabinet size. Code sets minimum clear floor space in front of the lavatory and a minimum distance from a toilet centerline, and the door must not swing into the vanity, so a cabinet that fits the wall can still fail the room. Confirm the clearances before you size the box.

Code sets the floor: a toilet centerline ≥15″ from the vanity edge (IRC R307.1 / IPC 405.3.1) and ≥21″ of clear floor in front of the lavatory, and the entry door must not swing into the vanity. NKBA’s 18″ and 30″ make the room comfortable.Source: IRC R307.1 / IPC 405.3.1 (fixture clearances); NKBA Bath Planning Guidelines 2 & 6See the Bathroom vanity clearances in plan diagram →(opens in a new tab)

The height-and-sink comparison explains why the sink type, not the cabinet alone, sets the finished height. A drop-in sink rides a standard cabinet, a vessel bowl sits on a shorter one so the rim still lands in the comfort band, and an accessible lavatory caps the rim height with open knee space below. Pick the sink first; the cabinet height follows from it.

The cabinet height follows the sink: a standard 32–34½″ cabinet + ¾″ top lands the rim in the 34–36″ comfort band; a vessel bowl adds 4–6″ so its cabinet ships ~30″; an ADA lavatory caps the finished rim at 34″ AFF with open knee clearance. Pedestal and wall-mount lavatories have no cabinet — the fixture sets the rim.Source: ICC A117.1-2017 §606 (ADA lavatory rim ≤34″ AFF); NKBA comfort-height guidanceSee the Vanity height by sink type diagram →(opens in a new tab)

The rough-in elevation is why a double vanity needs a minimum width, not just two sinks drawn side by side. Each drain and supply set stubs out at a set height, and two sinks must keep their centerlines a minimum distance apart, so a double vanity runs sixty inches or wider. Space them closer and the faucets and traps crowd; the calculator holds the spacing.

Rough-in: the drain stubs 18–20″ above the finished floor, the supplies 20–22″. An 8″ widespread faucet drills 3 holes (one 4″ each side of center); centerset is 3 holes 4″ apart; single-hole is 1. Two sinks need centerlines ≥30″ apart (IRC P2705.1.5; NKBA 36″), so a double vanity runs 60″ or wider.Source: IRC P2705.1.5 (fixture spacing); standard lavatory rough-in heightsSee the Bathroom sink rough-in heights and double-vanity centerline… diagram →(opens in a new tab)

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Plan disposal before you start

Smaller jobs still produce more debris than a few trash bags can hold. Check what's allowed in a dumpster and which disposal option fits the scope.

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How to Use This Calculator

  1. Pick your bath type — powder room, full bathroom, or primary / master. Loads sensible defaults for vanity width, depth, height, sink type, and accessories.
  2. Enter or override vanity dimensions: width (in 6" increments — 18, 24, 30, 36, 42, 48, 60, 66, 72, 84), depth (21" standard; 18" tight; 24" matches kitchen), and height preference (standard 30–32", comfort 34½", ADA ≤ 33¼", or vessel-adjusted ~30").
  3. Pick mounting: floor-standing (toe kick), furniture-style with legs, or wall-mount / floating (requires in-wall blocking).
  4. Pick sink type: drop-in / self-rimming (any top), undermount (stone/quartz top required), vessel (cabinet auto-shortens), integral cultured-marble combo (no cutout), pedestal or wall-mount (no vanity).
  5. Pick sink count (single up to 60"; double 60"+ to meet IRC 30" centerline-to-centerline minimum) and faucet config (single-hole, 4" centerset, 8" widespread, or wall-mount).
  6. Pick tier: RTA / stock / semi-custom / custom. Drives door style, finish quality, and lead time. Bath cabinets are smaller scope than kitchen but use the same construction grades.
  7. Add accessories: linen storage (vanity-side, tall 18", tall 24", or linen+hamper combo), medicine cabinet (surface-mount or recessed in single / double / multi-stud bay), and mirror (frameless, framed, designer, or LED-backlit).
  8. Optional — enter wall length, toilet centerline distance, front clearance, and door swing. The calculator surfaces non-fatal warnings against IRC R307.1 / IPC 405.3.1 fixture clearances and NKBA Bath Planning Guidelines.
  9. Pick plumbing modification scope (reuse / minor relocation / major drain / convert single→double / floating-vanity drain) and toggle old-vanity removal.
  10. Click Calculate — see vanity dimensions, doors / drawers / hinges / slides / knobs / pulls, top width/depth, sink cutout dimensions per template, faucet hole count, plumbing rough-in heights, accessory line items, and IRC / NKBA layout warnings.

How vanity height changes by sink type

Standard vanity height is 30–32" (older homes, traditional design); comfort / counter height is 34½–36" (current new construction default — matches kitchen base). For vessel sinks the cabinet drops 4–7" to 28–30" so the finished rim (cabinet + ¾" top + 4–6" vessel rim) lands in the 34–36" comfort range. ADA-compliant lavatory rim is 34" max AFF (ICC A117.1 §606.3), so the cabinet must be ≤ 33¼" before the top — paired with knee-space construction (27" min H × 30" min W × 8" min D extending to 11" at 9" AFF) and pipe insulation per §606.5. The calculator handles the math automatically; just pick your height preference and sink type.

Frequently Asked Questions

How much do bathroom vanities cost?

Per HomeAdvisor / Angi / HomeGuide / Fixr 2025–2026 aggregates: 18–24" powder-room combos $200–$600 (cabinet + cultured-marble top + bowl); 30–36" full-bath combos $300–$1,200; 36" semi-custom cabinet only $900–$1,800; 60" double semi-custom $1,800–$3,500; 72" double semi-custom $2,500–$5,000; 84" double semi-custom $3,500–$6,500; custom 36–84" runs $1,500–$12,000+. Bath vanities typically run 20–30% higher per linear foot than equivalent kitchen base cabinets at the same tier — smaller runs amortize less and more decorative finishes are common in bath. Stock combos bundle the top + bowl into one SKU; semi-custom and custom price the cabinet only and the top is fabricated separately.

What's the difference between standard, comfort, and ADA vanity height?

Standard / vanity height is 30–32" tall — common in older homes and traditional design, still used for children and shorter users. Comfort / counter height is 34½–36" tall (cabinet) plus a ¾" top — matches kitchen base, now the default in new construction. ADA-compliant per ICC A117.1-2017 §606.3 limits the finished lavatory rim to 34" max AFF — so the cabinet plus top together cannot exceed 34". ADA design typically pairs a 33¼"-max cabinet with knee-space construction (27" min H × 30" min W × 8" min D, extending to 11" at 9" AFF) and pipe insulation per §606.5. Comfort-height vanities are NOT ADA-compliant; vessel-sink installations require a shorter cabinet (28–30") so the finished rim still lands in the 34–36" range. The vanity height diagram shows height by sink type.

How wide does my vanity need to be for a double sink?

60" minimum width to meet the IRC P2705.1.5 30" centerline-to-centerline minimum between two lavatories. NKBA recommends 36" centerline-to-centerline, which requires 72"+ of vanity width. The calculator enforces the 60" minimum and surfaces a warning if you try to fit two sinks in less. Single-sink vanities up to 60" wide are common; 60–72" is a transitional zone where you can choose single-with-side-drawers or true double-sink; 72"+ trends to double-sink in primary baths. The vanity clearances diagram shows the plan clearances.

What sink cutout do I need for a Kohler undermount lavatory?

Use the manufacturer's template — Kohler ships a printed paper template with each undermount lavatory. Reference cutouts per Kohler product specs: Caxton K-2210 17" oval (template 1151011-7) is bowl interior 16"×13" with cutout ~16⅜"×13⅛"; Archer K-2355 20" rectangular (template 1224722-7) is bowl interior 17⅝"×13"; Cursiva K-Whatever 20" rectangular cutout 17"×12⁹⁄₁₆". General rule: undermount cutout = bowl interior + ⅛" (typical fabricator allowance). Drop-in cutout = nominal sink size − 1". Vessel sinks require only a 1¾" round drain hole. Integral cultured-marble combos have no cutout — bowl is part of the top.

Do I need to reframe the wall for a recessed medicine cabinet?

Depends on the cabinet width and your wall framing. Standard 16" on-center 2×4 framing gives a 14½" clear stud bay. Recessed cabinets up to 14–16" wide drop in cleanly with no reframing — install ~$150–$250. Cabinets 20–24" wide require cutting and reinforcing one stud (with double 2×6 or 2×8 headers above and below) — adds $200–$400 reframing labor. Triple-view cabinets at 30–48" require cutting and reinforcing 2–3 studs and may interfere with electrical or plumbing in the wall — $400–$700 reframing. The calculator includes the reframing line item automatically when you select a recessed cabinet that requires it. Surface-mount cabinets (project 5–8" from finished wall) avoid all reframing — install ~$75–$200, just hang from studs.

Where does the drain rough-in go for a bathroom vanity?

Standard floor-standing vanity: drain centerline 18–20" AFF (acceptable range 16–22") through the back wall, centered on the sink basin (NOT necessarily centered on the cabinet). Hot/cold supplies at 20–22" AFF (typically 2–4" above drain), spaced 4" apart for 4" centerset faucets or 8" apart for 8" widespread. Floating / wall-mount vanities require the drain through the back wall at a raised height (14–18" AFF) shifted to clear drawer cutouts — no floor penetration possible since the cabinet has no floor contact. Drain pipe is 1½" trap arm; supplies are ½" copper or PEX. P-trap needs 6–8" vertical clear space below the drain; drawer-only vanities typically omit the lowest center drawer or use a U-cut to clear the trap. The sink rough-in diagram shows the rough-in heights and centerlines.

What clearances are required between the vanity and toilet?

Per IRC R307.1 / IPC 405.3.1: 15" minimum from centerline of toilet to any wall, fixture (vanity edge), or obstruction. NKBA recommends 18". The same 15" minimum applies between centerline of toilet and centerline of bidet, and between centerline of toilet and side wall. In front of the lavatory, IRC requires 21" minimum clear floor space; NKBA recommends 30". Centerline of lavatory to side wall is 15" minimum (IRC P2705.1.5) / 20" recommended (NKBA). Two adjacent lavatories on a double vanity: 30" minimum centerline-to-centerline (IRC P2705.1.5) / 36" recommended (NKBA). The calculator surfaces non-fatal warnings whenever your inputs fall below the IRC code minimum or NKBA recommended values.

Should I get a floating vanity?

Floating / wall-mount vanities are the dominant modern style — they make the floor read continuous (showcasing tile work) and they're easier to clean under. But they require in-wall 2×6 or 2×8 blocking between studs at bracket height before drywall, OR opening and patching existing drywall for retrofits ($300–$700 added scope). They also frequently force drain relocation from floor to back wall ($400–$1,200). Heavy floating vanities (60"+ with stone tops) need ¾" plywood backer plus 2×6 above and below, lag-bolted into studs, supporting 200–250 lb per manufacturer specs. Drywall anchors alone are insufficient — the bracket must hit studs or continuous blocking. Floating vanities are not 'cheaper' or 'simpler' than floor-standing — plan on $500–$1,500 of hidden trade-cost on average.