1/3 Inch Graph Paper

1/3 inch graph paper (approximately 8.5mm squares) fills the gap between the standard 1/4-inch and 1/2-inch grids. It is used in landscape architecture, where 1 square = 1 foot at a 1:12 scale; in education for students whose handwriting is too large for 1/4-inch but who want more precision than 1/2-inch provides; and for general drafting where an intermediate grid size is practical.

On a US Letter page with 0.5-inch margins, a 1/3-inch grid gives approximately 22 columns × 30 rows — about 660 squares. This is notably fewer than 1/4-inch paper (≈1,200 squares) but still provides a practical number of grid cells for most drawing and plotting tasks.

While 1/4 inch and 1/5 inch (engineering paper) are the most standardized US grid sizes, 1/3 inch is used informally in drafting, landscape planning, and educational settings. Some architectural scale rules use a 1/3-inch base unit, making this grid convenient for rough architectural sketches.