Kitchen dimensions and clearances

At a glance

Millimetres from the finished floor. CATAS is an Italian testing institute: we read its summary of BS EN 1116, not the standard. NKBA is the US National Kitchen & Bath Association.

Which numbers are standards and which are habit

A kitchen is the one room where a designer can find a great many confident numbers and almost no standard to quote them from. The sizes that the trade shares are set by BS EN 1116:2018 (coordinating sizes for kitchen furniture and kitchen appliances) and BS ISO 3055:2021. Both are paywalled and neither was read for this sheet. What we read is a three-page summary of the 2018 European edition by CATAS, an Italian wood and furniture testing institute, and three planning guides from UK kitchen retailers. The two agree: the retailers' 720 mm carcase on a 150 mm plinth under a 30 to 40 mm top lands inside the standard's 900 to 950 band.

Three things follow. First, the figures in the table above are conventions that the standard and the catalogues share, and each is marked with where it came from. Second, the aisle widths and the work triangle are not British at all: they come from the US National Kitchen & Bath Association (NKBA) planning guidelines, which are recommendations, not law. Third, the only kitchen clearances in building regulations guidance that we found are in Approved Document M volume 1, for accessible and wheelchair user dwellings in England.

The standard states that it does not apply to kitchens used in catering, according to the CATAS summary, so this sheet is about domestic kitchens, pantries and the guest kitchens of apartments and hotel suites. Strength is a separate matter: BS 6222-2 sets strength and durability levels for fitted kitchen units (G for general domestic use, H for heavy duty) and EN 14749 covers safety, according to SATRA, and neither gives sizes. Ask the partner workshop which level its units are tested to.

Unit sizes and heights

The overall height is a sum, and the sum is where mistakes start. A carcase 720 mm high, a 150 mm plinth or adjustable leg and a 40 mm top give 910 mm. A 30 mm top gives 900. The standard offers three fixed worktop heights, 850, 900 and 950 mm, each with a band of 0 to +50 mm (our reading of how the summary prints them), so 900 or 910 sits inside the middle band. It offers three so that the kitchen can suit the people who use it, and says nothing about worktops that adjust.

The gap above is the second sum. A wall unit hung 490 mm over a 910 mm worktop has its underside 1,400 mm above the floor; at the standard's 450 mm minimum the lowest it can hang is 1,360 mm. Lighting under the wall unit, a pelmet, a splashback and a hob hood all change the answer, so fix the level on the drawing and not by the unit.

Appliances sit in the same system. The summary gives minimum recess heights of 820, 870 and 920 mm for the three worktop heights, and nominal recess widths of 450 and 600 mm. It does not give the distance between a hob and a hood: the standard leaves that to the makers, so take it from the installation drawing of the appliance you have chosen.

Aisles, clearances and the work triangle

We found no UK requirement for a 1,067 mm aisle in an ordinary kitchen. The widths below are guidelines from the NKBA, which writes for US designers: the work aisle is at least 1,067 mm for one cook and 1,219 mm for more than one, measured between counter fronts, tall units and appliances, and a walkway is at least 914 mm. They are useful as a check on a plan that the building regulations are silent about, and a poor check for a plan that has to meet Approved Document M, where the figure is higher.

The work triangle joins the centre-front of the cooking surface, the sink and the refrigerator. The NKBA asks for each leg to be between 1,200 and 2,700 mm and for the three together to total no more than 7,900 mm, with no leg passing through an island by more than 305 mm and no full-height obstacle between two of the three work centres. A one-wall kitchen cannot form a triangle at all, and a bespoke plan with two cooks and a second sink often has more than three work centres, so use it to test a layout and not to design one. The drawing below is ours: its legs are worked out from the positions drawn.

Seating changes an island. For a diner on a stool, the NKBA asks for a knee space 610 mm wide and 457 mm deep at a counter 762 mm high, 381 mm deep at 914 mm and 305 mm deep at 1,067 mm, and 813 mm behind the diner where nobody passes. Stool heights and overhangs are worked through in the sheet on bar counter and stool heights.

Accessible kitchens in England (dwellings)

These are the only kitchen clearances we found in building regulations guidance, and they are narrow in scope: Approved Document M, volume 1, 2015 edition incorporating the 2016 amendments, for use in England, which covers dwellings. Volume 2, for buildings other than dwellings, is the subject of a separate sheet; we found no kitchen worktop or aisle figures in it.

• M4(2), accessible and adaptable dwellings, paragraph 2.24(b): a minimum 1,200 mm clear space in front of and between all kitchen units and appliances.
• M4(3), wheelchair user dwellings, paragraph 3.32(b): a minimum clear access zone 1,500 mm wide in front of and between all kitchen units and appliances.
• Paragraph 3.34, wheelchair accessible dwellings: a continuous worktop section at least 2,200 mm long holding the sink and drainer and the hob, either height adjustable or fixed and capable of being refixed at other heights, with no appliance beneath and open leg space capable of 700 mm clearance above the floor; a sink not more than 150 mm deep with insulation underneath; an oven space with its centre line 800 to 900 mm above the floor and a pull-out shelf beneath; at least 400 mm of worktop to one side of the oven and of a fridge or fridge freezer taller than the worktop; and drainage that adapts to worktop heights between 700 and 950 mm.
• Tables 3.3 and 3.4: the minimum length of worktop, including fittings and appliances, by number of bedspaces (below). Diagram 3.8 says to measure through the mid-line of the worktop and gives an example layout.

Whether a project must meet M4(2) or M4(3) is decided by the planning authority and building control, not by the designer; ask them, and ask whether a hotel suite or serviced apartment counts as a dwelling. Wales, Scotland and Northern Ireland have their own documents, which we did not read.

Where a bespoke kitchen departs, and what to fix on the drawing

A bespoke kitchen departs from the table in three honest ways, and each should be written on the drawing rather than assumed.

• Height for the user. The standard's three heights exist to suit different users, so a single bespoke height, a split height or an adjustable section is an application of the idea and not a breach of it. Say the height, say who it suits, and measure from the finished floor, including any build-up.
• Sizes off the module. The module widths are a starting point. A run drawn to the wall can be any width, but appliance openings are not flexible: take each opening from the appliance maker's drawing and confirm it before the carcase is cut.
• Clearances measured to the real fronts. Check the aisle between the actual door faces, handles and open appliance doors, not between the carcases. A dishwasher door open across a 1,200 mm aisle takes more of it than a drawing of the units shows.

Five things to fix before a kitchen drawing is signed: the worktop height and the sum behind it; the underside level of the wall units; the clear width of each aisle between real fronts; the appliance openings from the makers' drawings; and the survey dimensions the plan rests on, which the sheets on site surveys and on tolerances and scribing set out.

Worktop [910] mm above finished floor level, measured to the top surface: [150] mm plinth or adjustable leg, [720] mm carcase and [40] mm top. Underside of wall units [1,400] mm above finished floor level and not less than [450] mm above the worktop. Heights to be set for [the principal user / the access brief] and shown on the shop drawing.

Worktop depth [600] mm. Wall unit depth [320] mm including doors. Clear width between opposing fronts, including handles and open appliance doors, not less than [1,200] mm at [the main aisle]; checked on site before manufacture. Appliance openings to the maker's installation drawing for [appliance and model], confirmed in writing before manufacture.

Kitchen to meet Approved Document M volume 1, [2015 edition incorporating 2016 amendments], category [M4(2) / M4(3)], paragraphs [2.24(b) / 3.32 to 3.34]: clear space of [1,200 / 1,500] mm in front of and between units and appliances, and for M4(3) a worktop section as paragraph 3.34. Compliance to be accepted by [building control body / access consultant] before manufacture.

Standards and sources

• BS EN 1116:2018 Kitchen furniture, coordinating sizes: named; summary read (CATAS, June 2018).
• BS ISO 3055:2021 Kitchen equipment, coordinating sizes: named, not read.
• Approved Document M volume 1, 2015 edition incorporating 2016 amendments (England): paragraphs 2.24, 3.32 to 3.34, Tables 3.3 and 3.4.
• NKBA Kitchen Planning Guidelines with Access Standards (US): guidelines 3, 6 to 9, 11, 12, 16, 17, 23, 25.
• CATAS, UNI EN 1116:2018 Coordinating sizes for kitchen furniture and kitchen appliances (June 2018)

Questions we are asked

What is the standard height of a kitchen worktop in the UK?

Most catalogue kitchens come out at 900 to 910 mm: a 720 mm carcase, a 150 mm plinth or leg and a 30 to 40 mm top. BS EN 1116:2018, which we could read only in a testing institute's summary, gives three fixed worktop heights, 850, 900 and 950 mm, each with a band of 0 to +50 mm, and says they need not apply where the worktop adjusts. A bespoke kitchen can be set to the user.

How far should wall units be above the worktop?

The summary of BS EN 1116:2018 gives at least 450 mm from the worktop to the underside of the wall unit. UK planning guides give 450 to 500 mm, and one gives 490 mm over a 40 mm top. Under-unit lighting, a pelmet, a splashback or a hood can raise it, so fix the level on the drawing.

How wide should the aisle be between a worktop run and an island?

We found no UK building regulations figure for an ordinary dwelling outside the accessible categories. The US NKBA recommends 1,067 mm for one cook and 1,219 mm for more, measured between fronts. Approved Document M volume 1 asks for 1,200 mm clear in front of and between units for an M4(2) dwelling and 1,500 mm for an M4(3) wheelchair user dwelling, in England.

What is the kitchen work triangle and does it have to be followed?

It is the distances between the cooking surface, the sink and the refrigerator. The NKBA recommends each leg of 1,200 to 2,700 mm and 7,900 mm in all. It is a planning aid, not a rule, and it does not describe a one-wall kitchen or one with two cooks.

Do these sizes apply to commercial kitchens?

No. According to the CATAS summary, BS EN 1116 does not apply to kitchens used for catering, and this sheet does not cover them. It covers domestic kitchens, pantries and the kitchens of apartments and suites.

What does Approved Document M say about kitchen worktops?

Volume 1 for England asks for a minimum worktop length by number of bedspaces in wheelchair adaptable and accessible dwellings (Tables 3.3 and 3.4) and, for wheelchair accessible dwellings, a worktop section at least 2,200 mm long that adjusts or can be refixed at another height, with 700 mm of clear leg space (paragraph 3.34). Ask building control whether your project must meet it.