| Standard interior bathroom door | Grade 2 or equivalent ball-bearing butt hinges | 35–40 mm | 3 hinges for a typical door up to about 2,040 mm high | At least 45 kg per hinge set, subject to the door manufacturer’s rating | Stainless steel, or corrosion-resistant plated steel | Match hinge size, screw-hole pattern, handing, door thickness, and frame mortise depth | Use corrosion-resistant fasteners and avoid hinges with exposed low-grade steel in humid rooms |
| Heavy solid-core or acoustic bathroom door | Ball-bearing butt hinges with reinforced leaves | 40–45 mm | 3–4 hinges, depending on height, weight, and traffic | Choose a tested set rated above the complete door weight, including hardware | 304 stainless steel is a practical baseline for humid interiors | Confirm hinge bearing capacity, screw length, frame reinforcement, and clearance at the jamb | An additional hinge can reduce sag, but excessive hinges may require precise alignment |
| High-humidity or poorly ventilated bathroom | Stainless-steel butt hinges with protected bearings | 35–45 mm | Use the quantity required by door weight and height; commonly 3 or 4 | Select a tested rating with a clear safety margin over actual door weight | 304 stainless steel; 316 stainless steel for coastal or chloride-rich environments | Check that the visible finish, screws, pin, and bearing materials are all corrosion resistant | 316 stainless steel offers better resistance to chlorides, while ventilation remains essential |
| Glass bathroom or shower door | Purpose-designed glass door hinge; do not substitute a wood-door hinge | Commonly 8–12 mm tempered safety glass; verify the actual panel specification | Usually 2 hinges for smaller panels; follow the tested system limit | Use the hinge system’s certified panel-weight and panel-size limits | 304 or 316 stainless steel with compatible gaskets and liners | Verify glass thickness, cut-out dimensions, mounting direction, swing angle, and gasket type | Use only hinges tested for tempered glass; incorrect drilling or overtightening can cause breakage |
| Accessible or frequently used bathroom | Low-friction ball-bearing hinges or adjustable spring hinges where permitted | 35–45 mm | Normally 3 hinges; size and quantity must suit the door closer and opening force | Choose a commercial-duty rating appropriate to traffic and door weight | Stainless steel or durable commercial-grade plated steel | Check opening force, self-closing behavior, door closer compatibility, and clear opening requirements | Confirm local accessibility rules; hinge selection alone does not establish compliance |
| Fire- or smoke-rated bathroom door | Listed or certified hinges specifically approved for the complete door assembly | Varies by the tested door assembly | Use the quantity and spacing specified by the door assembly listing | Must meet the tested assembly’s load and cycle requirements | Use the material and finish permitted by the certification | Verify the applicable fire-rating, hinge listing, door label, frame, screws, and closer requirements | Do not replace certified hinges with visually similar hardware; assembly compatibility is critical |
| Retrofit using existing hinge locations | Same-size replacement butt hinge with matching hole pattern | Measure the existing door rather than relying on nominal size | Keep the original quantity unless the door manufacturer approves a change | Equal to or greater than the original hinge specification | Match the existing finish; use stainless replacement screws where suitable | Measure leaf height, width, thickness, corner radius, pin diameter, and screw-hole spacing | A precise match avoids new mortises, reduces labor, and lowers the risk of weakening the frame |
| Premium long-term installation | Heavy-duty ball-bearing hinges with replaceable or protected bearings | 35–45 mm, subject to the door design | 3–4 hinges based on door dimensions and weight | Select a rating with a meaningful margin above actual static and operating loads | 316 stainless steel in coastal settings; 304 stainless steel for most indoor bathrooms | Check test standard, cycle rating, corrosion resistance, adjustability, and serviceability | Higher initial cost can reduce sagging, replacement frequency, corrosion, and maintenance labor |