Hexagon graph paper, A4
A hex grid on A4 at 10 mm, the general-purpose size for mapping, tiling and organic chemistry.
Opens with these settings already loaded. Change anything you like, then download as PDF, PNG or SVG.
One grid, three unrelated audiences
Hex paper gets used by people who have nothing else in common. Tabletop players draw overland maps on it because a hex has six equidistant neighbors, which makes movement fair in every direction in a way a square grid does not. Chemists draw ring structures on it. Quilters and tilers use it for tessellation. All three want the same geometry and different sizes, which is why the spacing is adjustable rather than fixed.
Pointy top, and what the measurement refers to
These are pointy-top hexagons, with a vertex at the top rather than a flat edge. The spacing figure is the circumradius, the distance from the center to a corner, so the point-to-point height is twice that and the flat-to-flat width is about 1.73 times it. This trips people up when they measure a printed sheet across the flats and get a smaller number than they set. Measure corner to corner through the center.
Choosing a size for the job
Ten millimeters is a reasonable default for general work. For miniatures on the table you want much larger, around one inch point to point, so a standard base sits inside a cell. For overland campaign maps you want much smaller, around a quarter inch, so a whole region fits on one sheet. For chemistry, 5 mm keeps ring structures compact enough to write substituents around.
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.