The Thirty-One Kitchen Design Rules, Illustrated

Index to Rules

Starting in 1944 the University of Illinois conducted a number of studies of kitchen design and developed the fundamental design principles that are still very much in use. These days the National Kitchen & Bath Association updates and publishes these basic design standards.

Methodology & Overview

The NKBA Kitchen & Bathroom Planning Guidelines with Access Standards is a collection of illustrations and planning suggestions to aid professionals in the safe and effective planning of kitchens and bathrooms. These guidelines are excerpted from the National Kitchen & Bath Association Professional Resource Library Kitchen Planning and Bath Planning volumes. Designers and those interested in becoming kitchen and bath design professionals benefit by studying the complete body of knowledge found in the NKBA Professional Resource Library.

These flexible and easy-to-understand guidelines were developed under the guidance of the NKBA by a committee of professionals. The committee completed in-depth historical reviews of planning guidelines dating back to 1920. The guidelines published in this booklet reflect a composite of the historical review, current industry environment, future trends, consumer lifestyles, new research, new building codes, and current industry practices; as well as a Kitchen Storage Research Project conducted by Virginia Polytechnic Institute.

The "Universal Design Guideline Access Standard" is a relatively new addition to the guidelines. It defines the rules for kitchens intended for use by persons with less than full physical abilities.


Get an official copy of the consolidated Kitchen & Bathroom Planning Guidelines.

A kitchen that follows all of these rules is almost guaranteed to be both functional and safe. See how many rules your existing kitchen violates for a better understanding of why it may seem awkward and hard to use.

While these guidelines are a good start, they do not substitute for competent kitchen design. Design encompasses these rules and much more. It's the "much more" part that gets novice designers in trouble. A new kitchen is a major investment, and not something you are going to want to do over because the first design was not quite right. So, invest in a good design. It's money well spent.

Other Rules and Guidelines

These are not the only kitchen design "rules". Designers, carpenters, cabinetmakers, plumbers and electricians have worked out some rules of thumb over many years that may not rise to the level of "standards", but represent accepted practice proven over time to be effective. We have included these in notes and comments where applicable.

Legend

Code Requirement: Refer to national building and access codes. Your local code authority may have modified or added to these national requirements.

Universal Design Guideline: Refer to NKBA recommendations for universal design.

ADA/ANSI Guidelines: Refer to Americans with Disabilities Act guidelines and recommendations published by the American National Standards Institute for universal design. These may or may not be mandated by local building codes, but are required in some federally subsidized housing.

Notes: Remarks by the publishers of the rule or standard.

Comments: Our own observations and clarifications. We use comments to introduce rules and guidelines from other sources as well as discuss our own experience with and application of these guidelines.

Guideline: The clear opening of a doorway should be at least 32" wide. This requires a minimum 34" or 2'-10" door.

Code Requirement: No national Code Requirement.

Universal Design Guideline: The clear opening of a doorway should be at least 34’’. This would require a minimum 36" or 3’-0’’ door.

Guideline: No entry door should interfere with the safe operation of appliances, nor should appliance doors interfere with one another.


Code Requirement: No national Code Requirement.

Universal Design Guideline: In addition, the door area should include clear floor space for maneuvering which varies according to the type of door and direction of approach. See ADA/ANSI Guidelines below.

Comments: Door interference can be subtle. For example, we like to locate refrigerators and pantries at the edge of the kitchen so that snack-seekers can get what they want without crossing into the main, working part of the kitchen. However, there is a good risk that the door of a refrigerator located next to an entry door will block entry when the refrigerator door is open. If cabinets are improperly spaced, the doors of two adjacent cabinets may strike each other. In kitchen remodels, working within an existing space, such problems may be unavoidable. But, they should be avoided if possible.

Guideline: In a kitchen with three work centers the sum of the three traveled distances should total no more than 26 feet with no single leg of the triangle measuring less than 4 feet nor more than 9 feet.

Universal Design Guideline The kitchen guideline recommendation meets Universal Design Guideline standards.

Code Requirement: No national Code Requirement.

Comments: The concept of a kitchen work triangle was developed in the early 20th century, and has now been superseded by more modern concepts such as integrated work zones. It does not work in every situation. For example, in a Pullman kitchen where the sink, cooking surface and refrigerator are on one wall, no triangle of any kind is possible. Nonetheless, for most kitchens, it remains a valuable preliminary gauge of how well a kitchen design is likely to function.

Guideline: A full-height, full-depth, tall obstacle should not separate two primary work centers. A properly recessed tall corner unit will not interrupt the work flow and is acceptable. (Examples of a full-height obstacle are a tall oven cabinet or pantry cabinet.)

Code Requirement: No national Code Requirement.

Universal Design Guideline: The kitchen guideline recommendation meets Universal Design Guideline standards.

Guideline: No major traffic patterns should cross through the basic work triangle.

Code Requirement: No national Code Requirement.

Universal Design Guideline: The kitchen guideline recommendation meets Universal Design Guideline standards.

Comments: Clearly this rule is an ideal standard for new kitchens. But, in a great many existing kitchens built before 1970, the kitchen is also a hallway leading to the back door or basement. The major traffic pattern is straight through heart of the kitchen work triangle.

Unless significant alterations are made to the structure of the house, there is usually little that can be done about it. If possible, however, locate the sink and range or cooktop out of the traffic path. If the refrigerator is in or adjacent to the path, it does little harm.

Quite often the the aisles in the kitchen triangle can be widened by adjusting the depth of adjacent cabinets, but not below 21" of depth.

Guideline: The width of a work aisle should be at least 42” for one cook and at least 48” for multiple cooks. Measure between the counter frontage, tall cabinets and/or appliances.


Code Requirement: No national Code Requirement.

Universal Design Guideline: Kitchen guideline recommendation meets Universal Design recommendation. See Code References for specific applications.

Guideline: The width of a walkway should be at least 36”.

Code Requirement: No national Code Requirement.

Universal Design Guideline: If two walkways are perpendicular to each other, one walkway should be at least 42” wide.

Rule 8 - Traffic Clearance at Seating


Guideline: In a seating area where no traffic passes behind a seated diner, allow 32” of clearance from the counter/table edge to any wall or other obstruction behind the seating area.

Code Requirement: No national Code Requirement.

Universal Design Guideline: In a seating area where no traffic passes behind a seated diner, allow 36” of clearance from the counter/table edge to any wall or other obstruction behind the seating area.


Code Requirement: No national Code Requirement.

Guideline: If a kitchen has only one sink, locate it adjacent to or across from the cooking surface and refrigerator.

Code Requirement: No national Code Requirement.

Universal Design Guideline: Plan knee spaces at the sink to allow for a seated user. Recommended minimum size for a knee space is 36” wide x 27” high x 8” deep, increasing to 17” deep in the toe space, which extends 9” from the floor. Insulation for exposed pipes should be provided.

Comments: In a pullman kitchen in which the entire kitchen is placed against one wall, the sink must necessarily be located between the cooktop and refrigerator. This rule allows no other placement.

Guideline: Include at least a 24” wide landing area [Note C] to one side of the sink and at least an 18” wide landing area on the other side.

Code Requirement: No national Code Requirement.

Universal Design Guideline:
Kitchen guideline recommendation meets Universal Design standards.

Comments:
In Universal Design, it is not uncommon for the cabinet containing the sink to be lower than the adjacent cabinets. Hence the standard in Note A that allows the landing area to be at a different level than the sink countertops as long as there is at least 24" of same-level countertop space on one side of the sink.

Guideline: Include a section of continuous countertop at least 30” wide x 24” deep immediately next to a sink for a primary preparation/work area.

Code Requirement: No national Code Requirement.

Universal Design Guideline: A section of continuous countertop at least 30” wide with a permanent or adaptable knee space should be included somewhere in the kitchen.

ADA/ANSI Guidelines: In a kitchen, there should be at least one 30” wide section of counter, 34” high maximum or adjustable from 29” to 36”. Cabinetry can be added under the work surface, provided it can be removed or altered without removal or replacement of the work surface, and provided the finished floor extends under the cabinet. (ANSI A 117.1 8.04.6.3, 1003.12.6.3)

Comments: There are very limited circumstances under which the countertop next to a sink should be less than 30" wide. If the countertop is deeper than the standard 25", the minimum width should, nonetheless, remain 30". As a practical matter, it is sometimes necessary to decrease the depth of the countertop (never to less than 21"). If this is the case, increase the width of the countertop work area to 36".

Guideline: Locate nearest edge of the primary dishwasher within 36” of the nearest edge of a cleanup/prep sink.

Code Requirement: No national Code Requirement.

Universal Design Guideline: Raise dishwasher 6” – 12” when it can be planned with appropriate landing areas at the same height as the sink.

ADA/ANSI Guidelines: A clear floor space of at least 30” x 48” should be positioned adjacent to the dishwasher door. The dishwasher door in the open position should not obstruct the clear floor space for the dishwasher or the sink. (ANSI A 117.1 804.6.3, 1003.12.6.3)

Comments: The modern dishwasher is an ergonomic disaster. It's much too hard to use. You have to bend and stoop a lot to load and unload it. You have to spend a lot of time opening and closing the top tray to reach the bottom tray. The bottom-hinged drawer gets in the way of people moving around the kitchen and makes it much harder for mobility impaired users to load and unload. It is not a very user-friendly or efficient appliance.

The solution is to raise the dishwasher off the floor so that the center of the appliance is about waist high. In kitchens where it is possible, that's what we do. The new drawer-style dishwashers are a vast improvement, but as of yet, very pricey. For more information of dishwasher placement, see Mise-en-Place: What We Can Learn About Kitchen Design from Commercial Kitchens. For more information about ergonomic kitchen design, see Body Friendly Design: Kitchen Ergonomics.

Guideline: Include at least two waste receptacles. Locate one near each of the cleanup/prep sink(s) and a second for recycling either in the kitchen or nearby.

Code Requirement: No national Code Requirement.

Universal Design Guideline: Kitchen guideline recommendation meets Universal Design Standard.

Comments: The best location for the trash and recycling bins in most kitchens is under the sink. This placement makes the best use of a cabinet space that is otherwise hard to use because of the piping and disposer

Guideline: At least 3” of countertop frontage should be provided on one side of the auxiliary sink, and 18” of countertop frontage on the other side, both at the same height as the sink.

Code Requirement: No national Code Requirement.

Universal Design Guideline: Plan knee spaces at, or adjacent to, the auxiliary sink to allow for a seated user. Recommended minimum size for a knee space is 36” wide x 27” high x 8” deep, increasing to 17” deep in the toe space, which extends 9” from the floor. Insulation for exposed pipes should be provided.

    Guideline: Include at least:
  1. 15” of landing area on the handle side of the refrigerator, or
  2. 15” of landing area on either side of a side-by-side refrigerator, or
  3. 15” of landing area which is no more than 48” across from the front of the refrigerator, or
  4. 15” of landing area above or adjacent to any undercounter style refrigeration appliance.

Universal Design Guideline: See ADA/ANSI Guidelines.

ADA/ANSI Guidelines: A clear floor space of 30” x 48” should be positioned for a parallel approach to the refrigerator/freezer with the center-line of the clear floor space offset 24” maximum from the center-line of the appliance. (ANSI A 117.1 804.6.6, 1003.12.6.6)

comments: Because the doors on a sidr-by-side refrigerator are always in the way of loading from either side of the appliance, the best choice of landing zone is on a countertop across from the refrigerator. If this is not possible start the landing zone at the edge of the door in its full open position, then add a minimum of 15" of clear countertop for the actual landing area.

Guideline: Include a minimum of 12” of landing area on one side of a cooking surface and 15” on the other side.

Code Requirement: No national Code Requirement.

Universal Design Guideline: Lower the cooktop to 34” maximum height and create a knee space beneath the appliance.

Guideline: Allow 24” of clearance between the cooking surface and a protected noncombustible surface above it.

Universal Design Guideline: Kitchen guideline recommendation meets Universal Design Standard.

Guideline: Provide a correctly sized, ducted ventilation system for all cooking surface appliances. The recommended minimum is 150 cubic feet of air per minute (cfm).

Universal Design Guideline: Ventilation controls should be placed 15” – 44” above the floor, operable with minimal effort, easy to read and with minimal noise pollution.

    Guideline:
  1. Do not locate the cooking surface under an operable window.
  2. Window treatments above the cooking surface should not use flammable materials.
  3. A fire extinguisher should be located near the exit of the kitchen away from cooking equipment.

Code Requirement: No national Code Requirement.

Comments: While there are no national building Code Requirement, it is very likely that a fire extinguisher in your kitchen is mandated by your local building or fire code.

Universal Design Guideline: Place fire extinguisher between 15” and 48” off the finished floor.

    Comments:
  • Put the fire extinguisher in plain view even if you don't like the "industrial look." National Fire Protection Association (NFPA) Guideline 10, Paragraph 6.1.3.1 states, "Extinguishers shall be conspicuously located where they will be readily accessible and immediately available in the event of fire." Paragraph 6.1.3.3.1 states, "Fire extinguishers shall not be obstructed or obscured from view."
  • A kitchen fire extinguisher must be rated for class K fires. These are fires fueled by flammable liquids and grease. Most fire extinguishes are rated for class K fires, but check to be certain.
  • When you install your fire extinguisher, read the instructions for using it to fight fires. Stopping to read the instructions while a fire is blazing is not a good idea, but using it without reading the instructions is an even worse idea.
  • Test your extinguisher at least every 6 months, more often if the manufacturer recommends a shorter interval, to make sure it is still charged and functioning. If it is not functioning, recharge or replace it.

Guideline: Locate the microwave oven after considering the user’s height and abilities. The ideal location for the bottom of the microwave is 3” below the principal user’s shoulder but no more than 54” above the floor. If the microwave oven is placed below the countertop the oven bottom must be at least 15” off the finished floor.

Code Requirement: No national Code Requirement.

Universal Design Guideline: Locate the microwave controls above 15" and below 48".

Comments: This guideline is a little vague when it comes to controls that have a vertical dimension, such as a keypad, but the illustrations that accompany the guideline seem to suggest that the entire pad should be below 48".

Guideline: Provide at least a 15” landing area above, below, or adjacent to the handle side of a microwave oven.

Code Requirement: No national Code Requirement.

Universal Design Guideline: Provide landing area in front of or immediately adjacent to the handle side of the microwave.

Comments: Typically there is a countertop near the microwave that will serve as a landing zone. However, if the microwave is located in a tall oven cabinet, it may be necessary to provide a landing area. If necessary, a pull-out shelf located under the microwave will work provided it is strong and stable enough to hold a minimum of 25 lbs.


Code Requirement: No national Code Requirement.

Comments: An oven in a range has to share the landing zone on one side of the range. One interpretation of Rule 24 (see below) is that the combined landing zone has to be 27" or larger. We think the proper interpretation is that the range/oven is one appliance, so the Rule 24 combination guideline does not apply. Landing zones surrounding range/oven combinations is adequately provided for by Rule 17 which requires a minimum of 27" divided between both side of the appliance, with a minimum of 15" on one side.

Universal Design Guideline: See ADA/ANSI Guidelines.

ADA/ANSI Guidelines: For side-opening ovens, the door latch side should be next to a countertop (ANSI A 117.1 804.6.5.1)

Guideline: If two landing areas are adjacent to one another, determine a new minimum for the two adjoining spaces by taking the larger of the two landing area requirements and adding 12".

Code Requirement: No national Code Requirement.

Universal Design Guideline: Kitchen guideline recommendation meets Universal Design Standard.

Guideline: A total of 158” of countertop frontage, 24” deep, with at least 15” of clearance above, is needed to accommodate all uses, including landing area, preparation/work area, and storage.

Notes: Built-in appliance garages extending to the countertop can be counted towards the total countertop frontage recommendation, but they may interfere with the landing areas.

Code Requirement: No national Code Requirement.

Universal Design Guideline: At least two work-counter heights should be offered in the kitchen, with one 28”– 36” above the finished floor and the other 36”– 45” above the finished floor.

Guideline: Specify clipped or round corners rather than pointed corners on all countertops.

Code Requirement: No national Code Requirement.

Universal Design Guideline: Kitchen guideline recommendation meets Universal Design Standard.

Distribution of Shelf and Drawer Space
Location Kitchen Size
Small Medium Large

Wall

Base

Drawer

Pantry

Miscellaneous

300”

520”

360”

180”

40”

360”

615”

400”

230”

95”

360”

660”

525”

310”

145”


Code Requirement: No national Code Requirement.

Universal Design Guideline: Plan storage of frequently used items 15” to 48” above the floor.

Comments: This design guideline is badly out of date. The whole notion of minimum shelf/drawer frontage is an attempt to quantify functionality that is not readily quantifiable. While the calculation may serve the need to have some math problems on the various NKBA certification examinations, it has little real world utility because it does not take into account the trend over the past twenty years of moving away from shelving in lower cabinets and toward drawers; nor does it distinguish between accessible and inaccessible storage.

    We treat the following as inaccessible storage:
  • The back of a base cabinet shelf behind the first 12",
  • The part of any upper cabinet or tall cabinet shelf behind the first 16", and
  • Any storage above 78" from the floor. (Actually, we use the upper arc of reach of the primary cook. For more information on arcs of reach, see Mise-en-Place: What We Can Learn About Kitchen Design from Commercial Kitchens .)
    To illustrate how differentiating between useful and inaccessible storage makes cabinet storage calculations more accurate, consider the following comparison:
  • A 24 inch-deep base cabinet with two shelves has the following frontage: 24" x 2' x 2 = 96 inches.
  • A 24 inch-deep base cabinet with two drawers has the same frontage: 24" x 2' x 2 = 96 inches.
All of the drawer space is accessible storage. To reach the back 12", just pull the drawer out. But, only the front 12" of the shelves in base cabinets is useful storage, the back 12" is inaccessible. To treat the two storage modalities as if they provided the same amount of useful storage is misleading and not useful. The drawers are more useful storage and their higher utility should be accounted for in calculating minimum frontage.

In our calculations we score inaccessible storage at only 1/2 the value of accessible storage.

The formula for the accessible part of the shelf remains the same: (width in inches) × (depth in feet) × (number of shelves), but it applies to just the front 12" of the shelf. So using the above example, the frontage of the accessible part of the base cabinet shelves is

24" × 1' × 2 shelves = 48" of frontage.

The revised formula for the back 12" of shelf is (width in inches) × (depth in feet) × (number of shelves) / 2. This gives the back half of the shelf a reduced frontage of 24" because the back of the shelf is only half as useful as the front of the shelf due to its inaccessibility. The calculation

24" × 1' × 2 shelves / 2 = 24" of frontage.

The total frontage for the base cabinet with two shelves is 48" + 24" = 72". The base cabinet with drawers retains its original frontage of 96". Now the comparison of frontage scores clearly shows the drawer cabinet to be more useful storage.

It is also usually possible to fit three or four drawers in a lower cabinet, while the maximum practical limit on shelves is two. If three drawers are used, the frontage calculation works out to 144" or double the storage of two shelves. If four drawers are installed, the frontage is 192" or 2.75 times of the maximum practical storage available on two shelves


Code Requirement: No national Code Requirement.

Universal Design Guideline: Plan storage of frequently used items 15” to 48” above the floor.

Guideline: At least one corner cabinet should include a functional storage device

Notes: This guideline does not apply if there are no corner cabinets.

Code Requirement: No national Code Requirement.

Universal Design Guideline: Kitchen guideline recommendation meets Universal Design Standard.

Guideline: GFCI (Ground-fault circuit-interrupter) protection is required on all receptacles servicing countertop surfaces within the kitchen. (IRC E 3802.6). Refer to IRC E 3801.4.1 through E 3801.4.5 for receptacle placement and locations.

Universal Design Guideline: Lighting controls should be placed 15” – 44” above the floor, operable with minimal effort, easy to read and with minimal noise pollution.

Comments: For more information on the structural components of the kitchen; the piping, heating and cooling, electricity and lighting, see Behind the Scenes - The Hidden Kitchen.

Guideline: In addition to general lighting required by code, every work surface should be well illuminated by appropriate task lighting.

Universal Design Guideline: Lighting should be from multiple sources and adjustable

Pantry Design Rules

Do you know the pantry design guidelines?

Every kitchen needs a pantry. Whatever the size or shape of your kitchen, it should include a convenient place to store groceries, and this critical storage requires careful thought and planning. It should be large enough to hold at least a week's worth or groceries, and close enough to the food preparation…(Continues>

Rev. 05/10/18