How to Draw Proportions Accurately: Six Ways to Measure What You See

Sight measuring with a pencil

Hold a pencil at arm’s length with your elbow locked, close one eye and line the tip up with one edge of the subject. Slide your thumb along the pencil to mark the other edge. That length is your unit. Without moving your thumb or bending your arm, compare it with other distances: the subject might be two and a half units tall and one and a half wide.

Two things make this accurate: always lock your elbow, so the distance from your eye stays constant, and keep the pencil flat, as if pressed against a pane of glass between you and the subject. Tilt it toward you and every measurement changes.

Angles, plumb lines and levels

Hold the pencil perfectly vertical and see what lines up. In a portrait, the inner corner of an eye might sit directly above the edge of a nostril. In a figure, the ankle of the standing leg is often directly below the pit of the neck. These vertical alignments are hard to judge by eye and very easy to check with a plumb line.

Do the same horizontally to see what is level with what, then tilt the pencil to match a slanted edge, such as a shoulder line, and carry that angle back to your drawing. Most proportion errors are really angle errors.

Draw the negative space

The shape between the subject and its surroundings is often easier to see accurately than the subject itself, because you have no assumptions about it. The triangle of space between an arm and the body, the gap between a chair’s legs, the sky between two branches: draw those shapes and the objects appear correctly between them.

This is especially useful with familiar objects. Your brain knows what a hand looks like and overrides what you see. It has no opinion about the shape of the gaps between the fingers.

Proportional dividers and grids

Proportional dividers are a pair of pointed arms with an adjustable pivot. Set the pivot for a ratio such as 1:2, measure a distance on the reference with the small end, and the large end gives the same distance doubled on your drawing. They are fast and precise for working from photographs.

A grid does the same job without tools. Draw a grid on the photo and a grid with the same number of squares on your paper. The ratio between the square sizes is your enlargement. A 2 cm grid on a 10 × 15 cm print becomes a 6 cm grid on a 30 × 45 cm drawing, a scale of 3. Copy what is in each square, one square at a time. Keep the grid lines very light on the drawing; they are tedious to erase.

Counting heads for figures

For the human figure, the head is the traditional unit. Drawing books commonly give an average adult as about seven and a half heads tall, while classical and fashion figures are drawn at eight or more to look taller and more elegant. Children have proportionally bigger heads: a toddler is roughly four heads tall, and the count rises through childhood.

Useful landmarks on an adult figure drawn at eight heads: the nipples fall about two heads down, the navel about three, the crotch about four, which is the midpoint of the body, and the knees about six. Real people vary, so measure your model or photo and use the head count only to notice when something is far off.

Check, then check again

Measure the largest relationships first, such as overall height against width, and the smallest last. A perfect eye in the wrong place is still wrong. After each stage, step back, flip the drawing in a mirror or photograph it and flip the image, and look for anything that leans, stretches or shrinks.

Measuring tools are training wheels for your eye. Use them heavily at first, then try to estimate a proportion before checking it. Over time your estimates get closer and you will measure less.

Questions before you start