Reference
Graph paper
Graph paper is paper printed with a regular grid, used for drafting, mathematics, sketching and early-stage interface design. The grid spacing you choose determines how much it constrains the drawing and how easy it is to read.
Spacings
Common grid sizes
1 mm grid
Fine drafting and precise measurements.
2 mm grid
Detailed sketching with subtle guidance.
5 mm grid
The classic school grid. Good for everyday notes and maths.
10 mm grid
Engineering layout, large diagrams.
¼ inch (6.35 mm)
The imperial equivalent of the 5 mm school grid.
⅛ inch (3.175 mm)
A finer imperial grid for technical work.
Major and minor lines
Most graph paper has two line weights: a faint fine grid and a darker major grid every fifth or tenth fine line. The major grid acts as a counting aid; without it, the eye loses count past four or five squares. The generator on this site lets you set how many fine lines fall between two major lines.
Printing accurately
For a grid to match a real ruler, you must print it at 100% / "Actual size" without scaling. A scaled print stretches every square slightly, which can throw off measurements when you transfer them to a physical object.