Bathroom Vanity Calculator
Calculates standard bathroom vanity dimensions (single sink 24", 30", 36", 48"; double sink 60", 72"), rough-in plumbing drain/supply pipe heights, side clearance (minimum 15" from toilet centerline), and mirror/lighting proportions.
Formula
Recommended Width = Available Wall Width - 2" (for side gap / filler); Mirror Width = Vanity Width × 0.75 to 0.85
1. Standard Available Vanity Widths: 24", 30", 36", 42", 48", 60", 72" 2. Maximum Safe Vanity Size = Available Width In - (Walls on both ends ? 2 in : 0) 3. Double Sink Minimum = 60 inches (30 inches per user center) 4. Drain Rough-In Height = 18" to 20" above finished floor (AFF) 5. Water Supply Rough-In = 21" to 23" AFF (spaced 8" apart)
Inputs
- Available Wall Width (inches)
- Sink Preference
- Vanity Height Standard
Worked example
Selecting and roughing in a double sink vanity in a 60-inch alcove.
Outcome: Selects a 60" wide double vanity. Comfort height is 36" AFF. Dual sink basins are centered at 15" and 45" from the left edge (30" on-center spacing). Recommended mirror: Two 24" × 36" mirrors or one 54" continuous mirror. Rough-in dual drains at 19" AFF.
What is the difference between standard vanity height and comfort height?
Traditional bathroom vanities were built at 31 to 32 inches high to accommodate children. Modern "Comfort Height" vanities are 36 inches high (the same height as kitchen countertops), reducing painful lower back bending for adults.