The interior design guide. A definitive knowledge base for interior designers.

From first principles to the finishing touches: shell, surfaces, space planning, furniture, electrics, plumbing and joinery, in the order a project runs.

The Lexicon.

Every term, in plain words.

From hue and light reflectance to bonding and kick space, every term the guide uses has a short definition, what to know in practice and the pages that use it.

Use the guide in your AI assistant.

Connect Claude or ChatGPT.

The guide has an MCP server, so your assistant can search it, read its pages and cite them while it answers you. It is free, read-only, and needs no account or key.

Connect to Claude
Open docs
All sections

The interior design guide.

A definitive knowledge base for interior designers.

Eleven chapters take a home from first principles to the moment you show it to the client. Start with Foundations and read in order, or search for a topic, a term or a rule of thumb.

Chapters.

Eleven steps, from principles to presentation.

Keep reading.

Where to go next.

Sections.

Keep reading.

Where to go next.

Space,

measured from the body out.

A room is not its floor area. It is the distances between people, furniture and walls, and every one of those distances comes from the human body: how tall we stand, how far we reach, how much room we need to sit, pass and turn. Learn the body’s numbers, and plans, clearances and drawings all follow from them.

The body is the unit.

Every dimension starts here.

Vitruvius described the well-made body fitting both a square and a circle; Leonardo drew it; Le Corbusier turned it into the Modulor, a scale of dimensions built on a 183 cm man with his arm raised to 226 cm. Today it is called anthropometrics. The figures below are for an average 175 cm adult. Real people range from about 150–190 cm, so design for the range: heights for the shortest user, clearances for the largest.

Eye height

163cm

Standing. Seated, about 120. It sets art, mirrors and views.

Shoulders

45–50cm

Wide, about 30 deep: the body’s footprint in plan.

Elbow

108cm

Worktops sit 10–15 below it: about 90–95 cm.

Reach

210cm

Arm raised. Shelves people use daily stop near 190.

Positions set the distances.

Stand, walk, sit, lounge, reach, roll.

The same body takes up different space in each position. Seat heights come from the lower leg, table heights from the seated elbow, shelf heights from reach. A wheelchair user needs a 150 cm circle to turn; plan one in at least the bathroom, kitchen and entry, and every home works for longer.

Standing
Walking
Sitting
Lounging
Reaching
Wheelchair

Point at each figure to see the position in use. Dimensions in cm.

From body to clearance.

The space around the furniture.

A clearance is the free floor a body needs to use something: to pull a chair out, get into bed, pass another person or open a dishwasher. Draw it as a zone in plan, and the furniture plan almost lays itself out. Main circulation routes want 90 cm clear; where two people pass, 120.

Pull a chair out and stand up: 75–90 cm behind every chair.

Get in from either side and walk round the foot: about 70 cm.

One person needs 90 cm; two people passing need 120 cm.

Open drawers and the dishwasher with room to stand: 100–120 cm between runs.

Dimensions in cm. Point at each figure to see its clearance in use.

All clearances, minimum and comfortable
SituationMinimumComfortableWhy
Main circulation route90 cm100–120 cmOne person walking with something in their hands
Two people passing110 cm120 cmTwo shoulder widths plus a gap
Behind a dining chair75 cm90 cm+To stand up; more if someone walks behind
Dining place setting55 cm60–70 cmElbow room per person along the table
Beside a bed60 cm70 cmTo get in and make the bed
Kitchen aisle100 cm120 cmOpen doors and drawers; two cooks
Sofa to coffee table40 cm45 cmKnees, and still within reach
Wheelchair turning150 cm circle150 × 170 cmA full turn without reversing

Distance between people.

Space is social, too.

The anthropologist Edward T. Hall measured how close people stand depending on their relationship. Called proxemics, it explains why seating more than about 3 m apart kills conversation, and why a bench that forces strangers within 45 cm stays empty.

Intimate

0–45cm

Partners, children. A shared sofa.

Personal

45–120cm

Friends talking. A dining table’s width.

Social

1.2–3.6m

Group conversation. Keep living-room seats inside 3 m.

Public

3.6m+

Addressing a room. Too far for a home’s seating.

Questions.

What people ask most about space and layout.

What size rug goes under a queen or king bed?

Choose a rug that reaches about 50–60 cm beyond each side of the bed, and start it just in front of the bedside tables. For a queen bed that usually means about 240 × 300 cm; for a king, about 270 × 360 cm, laid across the bed. A smaller rug works too when it sits under the lower two thirds of the bed and still shows on both sides.

What size rug do I need for a living room?

Size the rug to the seating group, not the room. The front legs of every sofa and chair should rest on it, which in most living rooms means 200 × 300 cm or 240 × 300 cm. Leave a band of floor between the rug and the walls, about 30–45 cm, so the room does not look carpeted wall to wall.

How high should I hang pictures?

Hang a picture or a group so its centre sits about 145–150 cm above the floor, roughly eye level for a standing adult. Above a sofa or sideboard, leave 15–25 cm between the furniture and the bottom of the frame, so the two read as one composition.

What is the best layout for a living room?

The best layout faces the seating towards one focal point, keeps people within about 2.5–3 m of each other so they can talk, and leaves the main path clear. Pull furniture off the walls when the room allows, place the coffee table about 40–45 cm from the sofa, and keep at least 90 cm for walkways.

How do I plan a furniture layout?

Measure the room, including doors, windows, radiators and sockets, and draw it to scale. Mark the paths people take between doors first, then place the largest piece, then everything else around it. Check every route is at least 90 cm wide and every seat has a surface within reach before you buy anything.

How high should I hang curtains?

Hang the rod 10–15 cm above the window frame, or halfway between the frame and the ceiling, which makes the window and the room look taller. Extend the rod 15–25 cm beyond each side so the open curtains frame the glass instead of covering it, and let the fabric just touch the floor.

How high should I mount a TV?

Put the centre of the screen at seated eye level, about 105–110 cm above the floor for most sofas. Mounting it higher, above a fireplace for example, makes people tilt their heads back; if you must, tilt the screen down towards the seats.

How far should the sofa be from the TV?

A comfortable distance is about 1.2 to 1.5 times the screen's diagonal for modern high-resolution screens. For a 140 cm diagonal, that is roughly 170–210 cm. Further is fine for casual viewing; closer feels immersive but tiring.

How wide should a hallway be?

Plan for at least 90 cm, which lets one person walk comfortably, and 110–120 cm where two people need to pass or furniture lines the wall. Wheelchair routes need about 120 cm, with turning space of 150 cm at the ends.

What size rug goes under a dining table?

The rug should reach at least 60–75 cm beyond the table on every side, so chairs stay on it when pulled out. For a table for six, that usually means about 240 × 300 cm. Match the rug's shape to the table: round under round, rectangular under rectangular.

Units