FullCalculator

Ladder Angle Safety Calculator

By Wall Height

Calculate safe ladder placement from wall height

ft
ft

By Ladder Length

Calculate placement from known ladder length

ft
°

Formula

Base Distance = Height / 4 (4-to-1 rule); Ladder Length = sqrt(Height^2 + Base^2); Angle = atan(Height / Base)

Frequently Asked Questions

What is the 4-to-1 ladder rule?
The 4-to-1 rule states that for every 4 feet of height, the base of the ladder should be 1 foot away from the wall. This creates approximately a 75-degree angle, which is the safest angle for ladder use.
How far should a ladder extend above the roofline?
OSHA requires that a ladder extend at least 3 feet above the upper landing surface (such as a roofline) to provide a secure handhold when stepping on and off the ladder.

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