Learn recommended measurements and dimensions for effective bathroom design. From the experts of the National Kitchen & Bath Association (NKBA) and Kitchen and Bath Ideas magazine.
As the official partner of the National Kitchen & Bath Association (NKBA), Kitchen and Bath Ideas magazine endorses the following guidelines for bathroom planning.
The NKBA developed the bathroom planning guidelines to provide designers with good planning practices that consider users' typical needs. A committee of experts in bathroom design reviewed relevant research, lifestyle and design trends, and model building code requirements to ensure the guidelines promote the health, safety, and welfare of consumers.
The guidelines are used for academic and educational programs in bathroom design, evaluation of bathroom plans, and testing the competencies of designers seeking certification.
Bathroom Planning Guideline 1: Door Entry
Recommended: The clear opening of a doorway should be at least 34 inches wide. This would require a minimum 2-foot 10-inch door.
If the existing structure precludes changing the opening, then a minimum 2-foot door in allowable.
Bathroom Planning Guideline 2: Door Interference
Recommended: No entry or fixture door should interfere with one another and/or the safe use of the fixtures or cabinets.
Bathroom Planning Guideline 3: Ceiling Height
Bathroom Planning Guideline 4: Clear Space
Recommended: Plan a clear floor space of at least 30 inches from the front edge of all fixtures (i.e., lavatory, toilet, bidet, tub, and shower) to any opposite bath fixture, wall, or obstacle.
Bathroom Planning Guideline 5: Single Lavatory Placement
Recommended: The distance from the centerline of the lavatory to the sidewall/tall obstacle should be at least 20 inches.
Bathroom Planning Guideline 6: Double Lavatory Placement
Recommended: The distance between the centerlines of two lavatories should be at least 36 inches.
Bathroom Planning Guideline 7: Lavatory/Vanity Height
Recommended: The height for a lavatory varies between 32-43 inches to fit the user.
Bathroom Planning Guideline 8: Countertop Edges
Recommended: Specify clipped or round corners rather than sharp edges on all counters.
Bathroom Planning Guideline 9: Shower Size
Recommended: The interior shower size is at least 36x36 inches.
Code Requirement: The minimum interior shower size is 30x30 inches or 900 square inches, in which a disc of 30 inches in diameter must fit.
Bathroom Planning Guideline 10: Tub/Shower Controls
Bathroom Planning Guideline 11: Shower/Tub Control Valves
Shower and tub/shower control valves must be one of the following:
Bathroom Planning Guideline 12: Shower Seat
Recommended: Plan a seat within the shower that is 17-19 inches above the shower floor and 15 inches deep.
Code Requirement: Shower seat must not infringe on the minimum interior size of the shower (900 square inches).
Bathroom Planning Guideline 13: Tub/Shower Surround
Recommended: The wall area above a tub or shower pan should be covered in a waterproof material extending at least 3 inches above the showerhead rough-in.
Bathroom Planning Guideline 14: Grab Bars
Recommended: Plan grab bars to facilitate access to and maneuvering within the tub and shower areas.
Grab bars should be placed at least 33-36 inches above the floor.
Grab bars must be 1-1/4 to 1-1/2 inches in diameter and extend 1-1/2 inches from the wall.
Bathroom Planning Guideline 15: Glazing
Bathroom Planning Guideline 16: Tub/Shower Door
Code Requirement: Hinged shower doors shall open outward.
Bathroom Planning Guideline 17: Steps
Recommended: Steps should not be placed outside a tub.
If steps are used, a grab bar/handrail is mandatory.
Bathroom Planning Guideline 18: Flooring
Recommended: Slip-resistant surfaces should be specified for the general bath flooring, shower floors, and tub/shower bottoms.
Bathroom Planning Guideline 19: Equipment Access
Bathroom Planning Guideline 20: Toilet/Bidet Placement
Recommended: The distance from the centerline of toilet and/or bidet to any bath fixture, wall, or other obstacle should be at least 18 inches.
Code Requirement: A minimum distance of 15 inches is required from the centerline of toilet and/or bidet to any bath fixture, wall, or other obstacle.
Bathroom Planning Guideline 21: Toilet Compartment
Recommended: The size for a separate toilet compartment should be at least 36x66 inches with a swing-out or pocket door.
Code Requirement: The minimum size for a separate toilet compartment is 30x60 inches.
Bathroom Planning Guideline 22: Storage
Recommended: Provide adequate, accessible storage for toiletries, bath linens, and grooming and general bathroom supplies at point of use.
Bathroom Planning Guideline 23: Accessories
Bathroom Planning Guideline 24: Electrical Receptacles
Recommended: All ground fault circuit interrupter receptacles should be located at electrical appliance points of use.
Bathroom Planning Guideline 25: Lighting
Recommended: In addition to general lighting, task lighting should be provided for each functional area in the bathroom (i.e. grooming, showering).
Bathroom Planning Guideline 26: Ventilation
Recommendation: Plan a mechanical exhaust system, vented to the outside, for each enclosed area.
Code Requirement: Minimum ventilation for the bathroom is to be a window of at least 3 square feet of which 50 percent is operable or a mechanical ventilation system of at least 50 cubic feet per minute (CFM) ducted to the outside.
Bathroom Planning Guideline 27: Heat
Recommended: A supplemental heat source, i.e., heat lamp, toe kick heater, or floor heat, should be considered.
Code Requirement: All bathrooms should have an appropriate heat source to maintain a minimum room temperature of 68° F (20° C).