Proportion Grid Calculator — Scale Reference Images

A proportion grid divides both your reference image and drawing surface into equal squares. You then draw the contents of each small square one at a time, making it much easier to maintain accurate proportions when scaling up or down.

For most drawings, 4-6 columns works well. More squares (8-12) give you more accuracy for detailed subjects like portraits. Fewer squares (3-4) are fine for simpler subjects or quick compositions.

Yes. A proportion grid works for scaling up (enlarging) or scaling down (reducing). The grid preserves the relative proportions regardless of size change. The key is that both grids have the same number of rows and columns.

Use a hard pencil (2H or 4H) and a ruler to draw light lines on your drawing surface. Draw them lightly so they can be erased later. On your reference, you can draw directly on a photocopy or use a clear acetate sheet overlay.