Calculate the safe angle and positioning for an extension ladder.
Ladder Measurements
Safe Positioning
Positioning your ladder?
Enter the vertical height you need to reach to calculate the safe base distance and angle according to the 4:1 rule.
About this calculator
Overview
The '4-to-1 rule' is a safety guideline for setting up extension ladders. For every 4 feet of height you have to climb, move the base 1 foot away from the wall. This creates a safe angle of approximately 75.5 degrees.
💡
Pro Tips
Always extend the ladder 3 feet above the roofline if stepping off.
Place the ladder on firm, level ground.
Stand with your toes touching the ladder feet and extend your arms; your palms should comfortable reach the rungs.
!
Fun Facts
"The optimal safety angle for an extension ladder is 75.5 degrees."
"If the angle is too steep (>75.5°), the ladder may tip backward."
"If the angle is too shallow (<75.5°), the bottom may slide out."
