Ladder Angle Calculator
Work out the safe angle and base distance for a ladder against a wall.
Setting a ladder safely
A ladder leaned at the wrong angle is dangerous — too steep and it can tip back, too shallow and the base can slide out. There is a recommended angle, and a matching rule for how far the base should sit from the wall relative to its height. This works out that safe base distance, so you can set a ladder at the right angle.
Enter the ladder length or height to see the safe base distance.
The four-to-one rule
The well-known guideline is the four-to-one rule: for every four units of height up to where the ladder rests, the base should sit one unit out from the wall, which gives the recommended angle of about seventy-five degrees. It is easy to check on site and genuinely prevents accidents. Beyond the angle, a ladder should extend above the point you are climbing to, stand on firm level ground, and ideally be secured — but the angle is the foundation of ladder safety.
Questions & answers
What is the four-to-one ladder rule?
For every four units of height to where the ladder rests, set the base one unit out from the wall, giving the safe angle of about 75 degrees.
Why does the angle matter so much?
Too steep and the ladder can tip back; too shallow and the base can slide out. The right angle prevents both, and ladder falls are common.
Is anything uploaded?
No. The calculation happens in your browser.