2 cm graph paper, A4
Two centimeter squares on A4, deliberately large, for early number work and for planning at a glance.
Opens with these settings already loaded. Change anything you like, then download as PDF, PNG or SVG.
Large squares are a teaching tool
At 2 cm an A4 sheet holds about nine squares across and fourteen down. That is few enough to count at a glance, which is exactly what you want for early number work, arrays, area and simple coordinates. A child who is still developing fine motor control can place a mark deliberately inside a 2 cm square, and cannot inside a 5 mm one.
Also a planning grid
The same coarseness suits any layout where one square stands for something substantial: a week in a timetable, a room in a floor plan sketch, a bed in a garden. When the whole plan has to be visible in one view and read from a distance, a fine grid actively works against you. For seating specifically the seating chart sheet is the same idea in landscape.
Where it stops being useful
Above about 2 cm the grid has so few cells that you may as well rule the lines yourself, and the sheet starts to feel like a table rather than graph paper. If you find yourself wanting bigger squares, what you probably want is a larger sheet at the same spacing. A3 at 5 mm or 1 cm gives you more grid rather than a coarser one.
Printing it accurately
This only measures correctly if your printer doesn't rescale the page. In the print dialog set Scale: 100%, not "Fit to page" or "Shrink oversized pages". If you're not sure it worked, print the calibration page, measure the ruler on it with a real ruler, and it will tell you exactly what your printer is doing to the page.