Door Butt Hinge
Doors & Walls · 7 specs
Direct Answer
Standard door butt hinges under ANSI/BHMA A156.1 standardize hinge leaf dimensions, corner radius mortises, leaf thickness, and screw hole template patterns. Sized in 3.5×3.5" for 1-3/8" residential interior doors, 4.0×4.0" for 1-3/4" solid doors, and 4.5×4.5" for commercial ball-bearing fire doors, hinges maintain standardized spacing along door edges.
Source: ANSI/BHMA A156.1-2021 (Butt Hinges) / SDI-100 · Last reviewed Aug 28, 2026
Specs
| Governing Standards | ANSI/BHMA A156.1 / SDI-100 / NFPA 80 |
| 3.5" Residential Hinge | 3.5 × 3.5" (89 × 89 mm) | Leaf: 0.085" (2.2 mm) | 1-3/8" hollow-core doors |
| 4.0" Heavy Residential Hinge | 4.0 × 4.0" (102 × 102 mm) | Leaf: 0.097" (2.5 mm) | 1-3/4" solid-core entry doors |
| 4.5" Commercial Hinge | 4.5 × 4.5" (114 × 114 mm) | Leaf: 0.134"–0.180" | Ball-bearing fire doors |
| Corner Radius Types | Square corner | 1/4" radius (dime size) | 5/8" radius (quarter size) |
| Top Hinge Standard Spacing | 5.0 inches (127 mm) down from top edge of door to top of hinge |
| Bottom Hinge Standard Spacing | 10.0 inches (254 mm) up from finished floor to bottom of hinge |
Corner Radii and Router Mortising
Residential door hinges feature three distinct leaf corner styles:
- Square Corner: Traditional sharp 90° corners chiseled by hand in solid wood jambs.
- 1/4-Inch Radius (Dime Size): Features a subtle 0.25-inch curved corner matching the cut profile of a 1/2-inch router bit.
- 5/8-Inch Radius (Quarter Size): Features a pronounced 0.625-inch curved corner, the universal standard for automated CNC high-speed factory machining of pre-hung door packages.
Standard Vertical Hinge Spacing on Door Edges
Standard architectural practice dictates specific hinge positioning on an 80-inch (6/8) door:
- Top Hinge: Positioned 5 inches below the top edge of the door slab.
- Bottom Hinge: Positioned 10 inches above the bottom of the door slab (above floor sweep).
- Center Hinge (3-Hinge Doors): Positioned exactly equidistant between the top and bottom hinges.
Code Requirement: Heavy solid wood, fiberglass, and fire-rated doors weighing >50 lbs must utilize at least three ball-bearing hinges to prevent long-term hinge leaf sagging and binding.