Ladder Safety Calculator

Find a recommended ladder size and setup distance for extension ladders or stepladders. The calculator accepts the height to reach in feet or meters and returns recommended ladder size, minimum required length, setup distance, angle, and safety reminders.

How to use this calculator

Choose feet or meters, select extension ladder or stepladder, and enter the height from the ground to the work surface. Extension ladder results include base distance from the wall and angle. Stepladder results skip wall distance because the ladder is used open in A-frame position.

How it works

For extension ladders, the calculator adds 3 ft above the landing surface and uses a 4 to 1 setup ratio:

$setup\ distance = required\ height \div 4$

For a 12 ft reach height, required height is 15 ft, setup distance is 3.75 ft, and ladder length is about 15.46 ft. The calculator rounds that to a standard 16 ft ladder.

Safety reminders

Use this as a sizing aid only. Keep the base level, lock ladder sections, face the ladder, and keep your body centered between the rails. For exterior projects, pair ladder planning with the roofing calculator or paint calculator so material handling is planned before climbing.