Free Online Adjacency Matrix Maker for Architecture

How to Build an Adjacency Matrix in Four Steps

1. List the spaces. Type them in one at a time, or use Paste list and drop in the room schedule from your brief. Add an area in square metres if you have one; it is optional and only feeds the bubble diagram export.
2. Fill the triangle. Click a cell to step through the levels. Every pair of spaces has exactly one cell, so nothing gets forgotten, and you only fill the lower half because the relationship between A and B is the same in both directions.
3. Read the summary. The line under the grid counts how many pairs you have actually decided and names the space with the most essential links.
4. Export. PNG for a drawing, CSV for a spreadsheet, JSON to come back to it, or hand the whole thing to the bubble diagram maker.

If you want the theory behind the tool rather than the buttons, our guide to the matrix diagram in architecture covers what the grid is, where it sits in the design process, and how to read one.

What Each of the Four Levels Actually Means

Three levels are not enough and six are too many. These four cover the decisions a brief actually contains.

Mark	Use it when	What it does on plan
Essential	The two spaces need a door or a direct route between them	They share a wall, or a short direct link
Desirable	Being near helps, but a corridor between them is fine	Same zone, same floor, no direct door needed
No requirement	The pair genuinely does not care	Free for the plan to decide
Must be separated	Noise, smell, heat, hygiene, security or privacy makes closeness a problem	Distance, a buffer space, or a different floor

Leave a pair on no requirement only when you mean it. A matrix full of untouched cells looks finished and has decided nothing.

A Worked Example: Filling In a Small Office, Pair by Pair

Load the Small office preset and you get the finished version of what follows. It is worth walking through the reasoning once, because the value of a matrix is not the grid, it is being forced to answer twenty one questions you would otherwise answer by accident.

The brief has seven spaces: reception 22 m², meeting room 26 m², open workspace 120 m², kitchen 14 m², server room 6 m², WC 8 m² and a store of 6 m². Seven spaces make twenty one pairs, and every one of them gets a cell.

Start with the pairs you are sure about

Reception and WC is essential. A visitor who has to be walked through the workspace to find a toilet is a plan that failed at the brief stage. Meeting room and open workspace is essential too, because staff move between them all day and every extra metre is paid for many times over.

Open workspace and server room is essential, for a duller reason: cable runs. Distance costs money in containment and in latency for anything hard wired.

Then the ones that only need to be nearby

Reception and meeting room is desirable. Visitors go from one to the other, but a short corridor between them is fine and often better, because it stops meeting noise reaching the front desk. Open workspace and kitchen is desirable: staff want a break area close, not attached. Meeting room and kitchen is desirable for the same reason in reverse, since refreshments have to travel.

Now the ones that matter most and get skipped most

Kitchen and server room is must be separated. Heat, steam and water do not belong near equipment that fails expensively. Kitchen and WC is must be separated on hygiene grounds, and in many jurisdictions a lobby between them is not optional.

Those two marks are the reason to build a matrix at all. Nobody forgets that a meeting room should be near the workspace. People forget that the only remaining slot for the server room is the cupboard behind the kitchen, until the drawing is finished and the decision is expensive.

Finish the rest deliberately

The remaining pairs, store to reception, server room to WC, and so on, are genuinely no requirement. Leaving them on the neutral mark is a decision, as long as you looked at them. The summary line under the grid tells you how many pairs you have actually touched, which is the honest measure of whether the matrix is finished.

What Must Be Separated, by Building Type

Separation is the level people leave blank, so here are the pairs that come up again and again. These are prompts to check against your own brief and local regulations, not a substitute for either. For healthcare work the authority is the published guidance itself — NHS England’s Health Building Notes set out clinical space and separation standards in detail.

Building	Keep apart	Why
House	Bedrooms and plant or utility; WC and kitchen; bedrooms and the party wall of a neighbour’s living room	Noise at night, hygiene, and sleep
Office	Server room and kitchen; quiet rooms and the tea point; meeting rooms and the print area	Heat and water, then noise
Clinic	Clean store and dirty utility; waiting and plant; consulting rooms and any corridor that carries soiled loads	Infection control and patient dignity
School	Hall and library; music and general teaching; kitchen deliveries and pupil routes	Noise and safeguarding
Restaurant	Refuse store and the dining room; WC and food preparation; deliveries and the customer entrance	Smell, hygiene and first impressions
Laboratory	Write-up space and wet benches; sensitive instruments and lifts or plant	Safety, and vibration

If a pair on your project appears in that table, mark it before you mark anything else. Separations constrain a plan far harder than adjacencies do, because an essential link can usually be solved with a corridor while a separation needs distance you may not have.

Turning a Room Schedule Into a Matrix

Most briefs arrive as a schedule of areas rather than a list of relationships. Getting from one to the other takes about ten minutes.

1. Copy the room names into a single column in your spreadsheet, one per line, and put the area after a comma. Press Paste list in the tool and drop it in.
2. Merge the repeats. Ten identical classrooms do not need ten rows. Two rows, Classroom A and Classroom B, tell you everything about the relationship without producing a grid nobody will read.
3. Group the small support spaces. Cleaner’s cupboard, riser and comms closet can usually be one row called Service, unless one of them carries a separation rule of its own.
4. Fill the separations first, then the essentials, then sweep the rest.

How Many Spaces Before a Matrix Stops Helping

The number of pairs grows with the square of the number of spaces, so a matrix gets unreadable faster than people expect.

Spaces	Pairs to decide	In practice
5	10	A few minutes, easy to hold in your head
10	45	The sweet spot, where the grid starts earning its keep
15	105	Still workable in one sitting
25	300	Split into departments and give each one its own matrix
40	780	Nobody fills this in honestly. Group first.

On a large project the usual answer is two levels: one matrix of departments, then a matrix inside each department. The tool handles either, and JSON export means you can keep them as separate files that belong to the same brief.

Turning the Matrix into a Bubble Diagram

The matrix records relationships. It does not place anything. The next drawing does, and the tool will start it for you.

Press As bubble diagram and you get a file that our bubble diagram maker opens with its Load JSON button. The translation is literal:

• Essential becomes a solid line labelled essential.
• Desirable becomes a dashed line labelled desirable.
• Must be separated becomes no line at all, and the pair is listed in the diagram description so the rule travels with the file.
• Spaces with the most essential links start nearer the centre, since those are usually the ones everything else has to reach.
• Areas become bubble sizes, so the diagram stays roughly proportional to the brief.

Nothing in that file is locked. Drag the bubbles, change the colours, add zones. The point is that you begin from your own decisions rather than from an empty canvas.

The Four Presets, and When Each One Helps

• House. The clearest teaching example: public rooms cluster, bedrooms cluster, and the kitchen and the WC carry a separation mark that most beginners forget.
• Small office. Shows how a single large space, the open workspace, ends up connected to nearly everything, and why the server room sits away from the kitchen.
• Clinic. Ten spaces, which is where a matrix starts earning its keep. The nurses station shows up as a cluster of essential marks, and the plant room fills a whole row with separations.
• School. Grouping by function and by noise at the same time, with the hall and the kitchen pulling in different directions.

Loading a preset replaces what is on screen, so export first if you have work in progress.

Reading Zones Out of a Finished Matrix

A finished grid contains the zoning of the building, and you can see it without drawing anything.

• Look for blocks of dark cells. A group of spaces that are all essential to each other is a zone. In the clinic preset the consulting rooms, treatment, recovery and the clean store form one — the same grouping our hospital bubble diagram guide arrives at, and that is the clinical zone.
• Look for a column that is dark all the way down. That space is a hub. Everything needs it, so it belongs central. The summary line names it for you.
• Look for a row of separations. That space wants to be at the edge, or on another floor. Plant rooms usually produce one.
• Look for a space with no strong marks at all. Either it is genuinely flexible, which is useful to know, or you have not thought about it yet.

Those four readings are usually enough to sketch a zoning diagram straight from the grid, before any bubbles are drawn.

What the Summary Line Tells You

Under the grid the tool reports how many of your pairs are actually decided, how the marks split between the levels, the total area if you entered one, and the space with the most essential links.

That last figure is worth more than it looks. In the clinic preset it lands on the nurses station, which is the correct answer: the space that everything else needs is the space that belongs at the centre of the plan. On your own project it is a quick sanity check. If the most connected space is a store cupboard, either the marks are wrong or the brief is.

Where the Matrix Sits in the Chain

Each drawing adds one kind of information, and skipping a step means inventing that information later under time pressure.

Step	Adds	Still missing
Room schedule	What exists and how big	Every relationship
Adjacency matrix	Every relationship, decided once	Any position at all
Bubble diagram	Approximate position and size	Shape, structure, site
Zoning diagram	Grouping across the plan or the section	Dimensions
Schematic plan	Real dimensions, walls, structure	Detail

The name is borrowed from graph theory, where an adjacency matrix records which nodes of a graph are connected. An architectural brief is a graph: spaces are nodes and required proximities are edges, which is why the same grid works.

Running the Matrix With a Client

The grid is a better interview tool than a questionnaire, because it forces one question at a time and the questions are concrete.

Share your screen, load the space list, and go along the rows asking a single sentence for each cell: should these two be next to each other? Clients answer that easily even when they cannot describe how they want the building to work. What surfaces are the requirements nobody writes in a brief: the delivery route that must not cross the reception, the office the director wants away from the meeting room, the store that is really a second kitchen.

Fill the grid live rather than tidying it afterwards. A cell filled in front of the client is a decision they have agreed. A cell filled that evening is your assumption wearing their authority.

Other Notations You Will Meet

There is no single global standard for matrix marks — the construction industry reference Designing Buildings describes the technique without prescribing one, so a grid you receive from an engineer or a client may not use the four levels this tool uses. These are the conventions you are most likely to see, and how they map across.

Convention	Marks	Maps to
This tool	Essential, desirable, none, separated	The four decisions a brief usually contains
Closeness ratings from systematic layout planning	A, E, I, O, U, X	A and E become essential, I and O become desirable, U is none, X is separated
Numeric scale	1 to 4, or 0 to 3	Straight across, as long as the key states which end is strongest
Filled and open circles	●, ◐, ○ and a cross	The same four, which is why this tool uses those glyphs
Colour only	A red to green scale	Convert it, then add a symbol

The last row is worth a warning. A matrix that carries its meaning in colour alone stops working when it is printed in black and white, photocopied, or read by someone with a colour vision deficiency. Every cell in this tool carries a symbol as well as a colour for exactly that reason, and the exported PNG keeps both.

The convention matters less than the legend. Whichever you use, put the key beside the grid and use it the same way on every project, so a matrix you drew last year still reads this year.

Could You Just Use a Spreadsheet?

You can, and plenty of practices do. Conditional formatting on a square grid gets you most of the way. Three things are worth knowing before you choose.

A spreadsheet gives you the full square, so you fill every relationship twice and the two halves drift apart on a long project. It has no idea that a matrix is symmetrical. It also has no notion of a hub, so nothing tells you which space is carrying the most essential links. And getting a presentable image out of it usually means a screenshot.

What a spreadsheet does better is arithmetic. If your matrix needs weighted scores, trip counts between departments or a cost per metre of separation, build it in a spreadsheet and use this tool for the version that goes in front of people.

Common Mistakes When Filling One In

• Marking everything essential. If most cells are dark, the matrix says nothing. Essential should mean a door or a very short route, and most projects have surprisingly few of them.
• Skipping the separations. The single most common failure. Separations are what a matrix knows that a plan sketch does not.
• Listing every cupboard. Grain matters. Group small support spaces unless one of them carries its own rule.
• Filling it in alone after the meeting. The grid is only as good as the conversation behind it.
• Treating it as final. Site, structure and daylight will move things. The matrix is what you check the moved plan against, not a plan in itself.

Export Formats

Format	Good for
PNG	Portfolio sheets, client packs and reports. Drawn at twice screen resolution with the key underneath.
CSV	Spreadsheets. Full square grid plus a key row, so it opens in Excel or Sheets without editing.
JSON	Saving and reopening, or passing the matrix to someone else on the team.
Bubble diagram JSON	The next drawing. Opens in our bubble diagram maker.

Saving, Sharing and Coming Back

The tool keeps your work in your browser as you go, so closing the tab and returning on the same device picks up where you left off. That is convenience, not backup. Three habits are worth having.

• Export JSON at the end of a session and keep it with the project files. It is the only version that survives a cleared browser, a different computer or a colleague picking the work up.
• Export PNG when a decision is agreed. A dated image of the matrix as it stood when the client signed off is worth having when the brief changes in month four.
• Use CSV if the matrix has to live in a report that someone else will edit, since a spreadsheet is where those usually end up.

Nothing is uploaded anywhere. The whole tool runs in the page, which also means it keeps working if your connection drops mid-session.

Frequently Asked Questions

Where to Go Next

• Matrix Diagram in Architecture, the guide behind this tool
• Bubble Diagram Maker, the drawing that comes next
• Architectural Diagrams: Every Type Explained
• Bubble Diagram in Architecture

After the bubbles come the zones. Our free zoning diagram maker is the third step in the same chain: it takes the room list, gives every space measured area on a floor plate and reports what share of the plan each zone occupies. If you want the theory behind the grid first, read programmatic diagrams and spatial organization diagrams.