How to size a mind map and keep it readable

Decide the depth first

Depth is the harder limit to fix later, because a wide map can be narrowed and a deep one cannot be flattened without rewriting it. Decide how many levels you are allowing before you start typing, and write the number in the root note so you can check it against something other than memory.

Three levels below the root is usually the most a reader can hold at once: the subject at the top, a category in the middle, a specific item at the bottom. A fourth level is usually a note in disguise, because a reader has to keep the whole parent chain in mind to make sense of a leaf.

Depth also costs horizontal room. In the tree layout each level pushes the map further to the right, and a deep branch in one corner makes the whole map harder to fit on a screen. Three levels is a working limit rather than a rule imposed by the app.

• Decide the depth before you add any branch
• Three levels below the root is the working maximum
• Write the depth limit into the root note
• A fourth level is usually a note in disguise

Six to eight branches at the top

Six to eight top-level branches is the width a person can hold in one view without scrolling, and the number is a limit on your categories, not on your ideas. If you have ten branches, two of them are hiding the same idea, and merging them is a better fix than shrinking the map.

A branch count is really a claim about the subject. A map of a project with eight workstreams may be right, and a map of a single meeting with eight branches is usually eight things that were said rather than eight parts of a subject. Ask what each branch is a part of.

The rules for an effective map make the same point from the reader's side: if the first level cannot be scanned in a breath, the problem is the categories rather than the drawing. Width is the first thing a reader notices.

• Six to eight top-level branches is the readable width
• More than eight usually means two branches share an idea
• Each branch must be a part of the subject, not a topic
• Width is set by categories, not by how much you know

One screen of detail per branch

Give each branch one screen of detail. That means two to four children per branch, each child a short label, and the whole thing readable without zooming. If a branch needs more than that, the extra material belongs in a node note, which holds up to 80,000 characters of formatted text and stays searchable.

One screen per branch is a rule about attention rather than pixels. A reader working down a branch should never have to hold a second branch in mind at the same time, and should never have to zoom to read a label. If they do, the branch has outgrown its allowance.

In Canvasola the node note is where the overflow goes. Open the note on a branch and you get bold, italic, underline, bulleted and numbered lists, a link control and dictation, so the detail can be a proper piece of writing rather than a run-on label.

• Two to four children per branch
• Never zoom in to read a label
• Overflow detail goes into the node note
• A branch you cannot read in one screen needs splitting

Run the sprawl test

The sprawl test is a two-minute check you run before you show a map. Press F to fit the content to view, which frames all visible elements plus the mind map, and then look at the result. If the map is a thin band of branches, it is too wide. If it is a wedge running off the screen, it is too deep.

Then check the other end. Press M for the minimap, a small overview in the corner, and see whether the branches are spread evenly or whether one corner is a knot. A knot is the sign of a branch that has collected far more detail than its neighbors.

A map that fails the sprawl test is not broken, it is bigger than one screen, and Canvasola has honest answers for that. The mistakes guide lists the symptoms you are most likely to see.

• Press F and look at the fitted map, not the zoomed one
• A thin band means too many branches
• A wedge running off the screen means too much depth
• Press M and hunt for a knot in one corner

Split what no longer fits

When a map has outgrown one screen, split it rather than shrink it. Canvasola's layer tabs scope a map to one layer at a time, and a map can hold up to 8 layers. Put the material that belongs together on one layer, and the map becomes a set of readable maps that share a root.

Layers answer depth as well as clutter. A subject with eight levels of detail becomes two layers of four, and each layer keeps a depth a reader can follow. The 3D layer stack goes further and puts every layer on its own depth plane, with a trace mode for following links between layers.

The layers guide covers how to build layered maps, and the shortcut cheat sheet lists the keys that switch between the 2D and 3D views. In the 3D stack you also get camera presets, an explode slider and a PNG export of the 3D view.

• A map can hold up to 8 layers
• Layers fix depth as well as clutter
• Put one kind of material on each layer
• The 3D stack places layers on separate depth planes

Note: Deleting a layer keeps its nodes, so a layer you split badly can be removed and rebuilt without losing the work underneath.

Know the hard limits

Canvasola's limits are generous, and they are limits rather than targets. A map holds up to 2,000 nodes, each node label holds up to 8,000 characters, and a rich note holds up to 80,000 characters. A map can also carry 4,000 cross-links between nodes.

The numbers matter because they tell you where the real constraints are. If a map is approaching 2,000 nodes, the problem is not the tool, it is that one map is trying to be several maps. If a label is heading for 8,000 characters, the problem is that you are writing a paragraph on a branch.

Nothing about those ceilings makes a map readable, and a map can hit all of them and still be unusable. The working limits are much smaller: six to eight branches, three levels, one screen per branch. The hard limits only tell you when to stop and split.

• 2,000 nodes per map, 8,000 characters per label
• 80,000 characters per rich note, 4,000 cross-links
• Hitting a ceiling means split, not trim
• The working limits sit far below the hard limits

A checklist you can reuse

• A depth limit was chosen before the branches were added
• Nothing sits more than three levels below the root
• The top level has six to eight branches, no more
• Every branch has two to four children, each a short label
• The map was checked with F and with the minimap on M
• Detail beyond one screen per branch sits in node notes
• A map that outgrew one screen was split into layers

Common mistakes to avoid

• Ten branches at the top. More than eight top-level branches cannot be held in one view, and the extra ones usually overlap. Merge the overlapping branches before adding anything below them.
• A fifth level. Depth past three levels means a reader has to keep the whole parent chain in mind. Move the detail into a note or onto a second layer.
• Ten children under one branch. A branch with ten children is a branch that has become two branches. Split it and the map gets narrower as well as shorter.
• Shrinking the font to fit. Making labels smaller to squeeze a map onto one screen trades legibility for nothing. Split the map, or move detail into notes.
• Treating 2,000 nodes as a target. The ceiling is a safety limit, not a size. A map that needs the ceiling has stopped being one map, and layers will serve you better.

Frequently asked questions

How many nodes should a mind map have?

For a working map, far fewer than the ceiling. A root, six to eight branches and two to four children each gets you a few dozen nodes and a map that reads in one glance. The hard ceiling of 2,000 nodes exists so the app stays responsive, and approaching it is a sign to split rather than a goal to hit.

How deep can a mind map go?

Three levels below the root is the practical limit for a reader, and the tree layout adds horizontal room with every level. The app will happily hold a deep map, but a fifth level is a note in disguise and belongs in a node note or on a second layer.

What happens if I hit the node limit?

Nothing dramatic. A map holds up to 2,000 nodes and a label holds up to 8,000 characters, so you would have to work hard to reach them. If you are close, the map is doing too many jobs, and splitting it by subject or by layer is the fix.

Should a big map be split into separate documents?

Layers are the better first step, because a map can hold up to 8 layers and the layer tabs let you open one at a time, so the pieces stay in one file under one root. Separate workspace tabs are the next step, and their titles are generated and cannot be renamed, so keep a note of which tab holds which subject.

This guide is part of the mind map fundamentals collection. For the wider product tour, read the complete Canvasola guide, and keep the keyboard shortcut cheat sheet open while you work.