Perspective Calculator — Vanishing Points & Horizon

The horizon line represents eye level. Place it at 50% for a normal standing view, lower (30-40%) for a ground-level or worm's-eye view, or higher (60-70%) for a bird's-eye view. The horizon line determines the dramatic effect of your composition.

One-point perspective has a single vanishing point on the horizon and is used when viewing an object head-on (e.g. looking down a corridor). Two-point perspective uses two vanishing points and is used when viewing objects at an angle (e.g. the corner of a building).

Yes, vanishing points are often off the paper, especially in two-point perspective. You can tape extra paper to the sides, use a long ruler extending beyond your drawing, or calculate the positions mathematically using this tool.

The cone of vision is about 60 degrees — 30 degrees each side of your line of sight — and everything inside it looks natural. For a drawing to be free of distortion, the viewer should stand roughly 0.87 times the picture width away (the recommended viewing distance this tool reports). Place the vanishing points too close together, or stand too near, and the cone is exceeded and the perspective looks stretched.

The station point is the viewer's position in front of the picture. Because the two sets of edges meet at a right angle, the two vanishing points subtend a 90-degree angle at the station point. That places the station point on the semicircle whose diameter is the line between the vanishing points, so its distance from the picture plane is the geometric mean of the two centre-to-vanishing-point distances. With the vanishing points centred this is simply half the spread.