Ladder Height Calculator

Ladder height must account for the fact that you should never stand on the top rungs, and extension ladders must be set at the correct angle.

Step ladders:

• Never stand on the top two steps
• Maximum reach = ladder height + ~4 feet (your arm reach)
• A 6 ft step ladder gives ~10 ft reach

Extension ladders (4:1 rule):

• Set base 1 foot out for every 4 feet of height (75.5° angle)
• Top must extend 3 feet above the roofline for roof access
• Usable height = ladder length × 0.96 (accounting for angle and overlap)

Extension ladder formula:

Ladder length = (Working height + 3 ft overlap) / 0.96

Step ladder formula:

Ladder height = Working height - 4 ft (your reach)

Safety guidelines:

• Maintain 3 points of contact at all times
• Do not lean beyond the side rails
• Set up on firm, level ground