Why 5 mm is so common
Most exercise books sold outside the US use 5 mm squares. The grid is small enough to write normal-sized handwriting across two squares and fine enough to draw neat graphs without wasting space. It is the usual choice for:
- Secondary school maths: working out, fractions, equations and graphs.
- Science lab write-ups with small data plots.
- Bullet journals and planners where a faint grid helps layout.
- Knitting and cross-stitch charts, one stitch per square.
A darker line every 10 squares
Turn on Darker line every 10 to mark every 5 cm with a heavier line. That makes it quick to measure lengths straight off the paper. A darker line every 2 squares is not offered because it makes the sheet look busy; use 1 cm paper instead.
Printing 5 mm squares accurately
Small squares show printing errors quickly. A 3% shrink from “Fit to page” turns 40 squares (20 cm) into 19.4 cm. Always print at 100% / Actual size, then hold a ruler against the 1 cm mark at the bottom of the sheet. See how to print graph paper at actual size for each browser.
Light lines for writing on
For notes and handwriting, choose Light line weight in Gray or Blue: the grid guides your writing but stays in the background on copies and scans.