Graph paper, graphing paper, or millimeter paper is writing paper that is printed with fine lines making up a regular grid. The lines are often used as guides for plotting mathematical functions or experimental data and drawing two-dimensional graphs. It is commonly found in mathematics and engineering education settings and in laboratory notebooks. Graph paper is available either as loose leaf paper or bound in notebooks. It is becoming less common as computer software, such as spreadsheets and plotting software, has supplanted many of the former uses of graph paper. Some users of graph paper now print pdf images of the grid pattern as needed rather than buying it pre-printed. There are websites that will generate pdfs of graph paper to the user's specifications.
Quad paper is a common form of graph paper with a sparse grid printed in light blue or gray and right to the edge of the paper. This is often four squares to the inch for work not needing too much detail. It is sometimes referred to as quadrille paper.
Engineering paper is traditionally printed on light green or tan translucent paper. The grid lines are printed on the back side of each page and show through faintly to the front side. Each page has an unprinted margin. When photocopied or scanned, the grid lines typically do not show up in the resulting copy, which often gives the work a neat, uncluttered appearance. In the US and Canada, some engineering professors require student homework to be completed on engineering paper.
Genkō yōshi – A type of manuscript paper used in Japan, normally printed with 400 squares in two sets of 20 lines of 10, used for compositions written in vertical script.
Hexagonal paper shows regular hexagons instead of squares. These can be used to map geometric tiled or tesselated designs among other uses
Isometric graph paper or 3D graph paper is a triangular graph paper which uses a series of three guidelines forming a 60° grid of small triangles. The triangles are arranged in groups of six to make hexagons. The name suggests the use for isometric views or pseudo-three-dimensional views. Among other functions, they can be used in the design of trianglepointembroidery. It can be used to draw angles accurately,
Normal probability paper is another graph paper with rectangles of variable widths. It is designed so that "the graph of the normal distribution function is represented on it by a straight line", i.e. it can be used for a normal probability plot.
Polar coordinate paper has concentric circles divided into small arcs or 'pie wedges' to allow plotting in polar coordinates.
In general, graphs showing grids are sometimes called Cartesian graphs because the square can be used to map measurements onto a Cartesian (x vs. y) coordinate system. It is also available without lines but with dots at the positions where the lines would intersect.