75%
Cartesian quad graph paper is the foundation of mechanical drafting, data science, and mathematical analysis. Standard high school quad paper typically features 4 squares per inch (0.25-inch spacing) or 5 squares per inch (0.20-inch spacing), whereas European and scientific laboratory notebooks adhere to a metric 1.0 mm minor grid with heavy accent lines every 5 mm or 10 mm.
When engineering scale drawings by hand, each square represents a physical dimension (e.g., 1 square = 1 foot or 1 meter). If a browser scales down the document during printing, an architect or engineer verifying measurements with a scale ruler will encounter cumulative errors that distort calculations.
Minor grid lines should be rendered between 0.3 pt and 0.5 pt stroke thickness. This ensures pencil marks and pen strokes remain legible without visual competition from the underlying background matrix.