Where should I place the horizon line?

The horizon line represents eye level. At 50% (centre), the viewer is at a neutral height. Lower horizon (30-40%) creates a low viewpoint looking up — objects appear taller and more dramatic. Higher horizon (60-70%) creates a bird's-eye view looking down.

How far apart should vanishing points be?

For 2 and 3-point perspective, both horizon vanishing points should sit off the canvas — beyond its left and right edges. VPs crammed onto the page cause extreme foreshortening that looks distorted. As a rule of thumb, the separation between the two VPs should be at least 1.5 times the canvas width, which keeps your subject inside the cone of vision. This calculator places them 1.6 times the width apart, so each one lands a little beyond the opposite edge.

What is the cone of vision, and what is the angle of view figure?

The cone of vision is the roughly 60° field (30° each side of your line of sight) in which a drawing reads as natural — anything outside it gets stretched. It is a fixed artistic guideline and does not change with lens choice, so this calculator always shows 60°. The separate "angle of view" figure is the photographic horizontal field of view of the focal length you enter on a full-frame 36mm sensor: about 40° at 50mm (a fairly tight, natural-looking view), wider at 35mm and narrower at 85mm. Use it to match a drawing to a reference photo, not as the cone of vision itself.

When should I use each type of perspective?

Use 1-point for looking straight down a road or corridor. Use 2-point for most scenes with buildings at angles. Use 3-point for dramatic upward or downward views of tall structures. Most drawings use 2-point perspective.

Perspective Grid Calculator — Free Drawing Tool

How We Calculate This

Horizon Line

Horizon Y = Canvas Height × (Position% ÷ 100), measured down from the top edge. The horizon is your eye level.

Vanishing Points

For 1-point, a single VP sits on the horizon at the canvas centre. For 2 and 3-point, the two horizon VPs are spaced symmetrically about the centre at 1.6 × the canvas width apart, so both land just beyond the side edges (origin is the top-left corner, so the left VP has a negative x). Keeping them off the format holds your subject inside the 60° cone of vision. For 3-point, a vertical VP is added below the canvas when looking down (bird’s-eye) or above it when looking up (worm’s-eye).

Grid Spacing

Grid Spacing = Canvas Width ÷ Number of Divisions. This is an even frontal reference grid for laying out the picture plane and locating the VPs and horizon. It is construction guidance, not a metric projection — receding depth rows foreshorten and get closer together as they approach the horizon, which you draw by eye or with the distance-point method.

Frequently Asked Questions

Related Calculators

Pencil Grade Calculator

Find the right pencil grade range for your drawing style and subject matter. Covers graphite, charcoal and coloured pencil ranges.

Paper Size Calculator

Convert between A-series, imperial and custom paper sizes with area calculations. Includes weight and sheet count estimation.

Proportion Grid Calculator

Calculate grid dimensions for accurately scaling a reference photo or image onto your drawing surface. Free online grid calculator for artists.

Perspective Calculator

Calculate vanishing point positions and horizon line placement for one, two and three-point perspective drawings. Free calculator.

Drawing Scale Calculator

Convert real-world measurements to drawing scale and vice versa. Useful for architectural sketches and technical illustration.

Last updated: March 2026

All calculations are estimates. Always verify quantities before purchasing materials.