Enter the total height of the ladder into the calculator to determine suggested the ladder angle and base distance.

Ladder Angle Formula

The following formula is used to calculate a ladder angle: 

LA = atan(H/B)
  • Where LA is the ladder angle (degrees)
  • H is the height of the ladder
  • B is the base of the ladder

To calculate a ladder angle, take the inverse tangent of the height divide by the base of the ladder.

The base of the ladder should be 1/4 the height. For example, if a ladder is 12 feet high, the base should be at a minimum of 3 feet.

What is the correct ladder angle?

The most common recommended ladder angle is 75 degrees. A 75-degree angle creates a base that is 1/4 of the height, or in other words, the height to base ratio is 4:1.

How to calculate a ladder angle?

Example Problem:

The following example goes over the steps and information that is needed to calculate a ladder angle.

First, determine the height of the ladder. In this example, the height of the ladder is 20 feet.

Next, determine the base of the ladder. This is the distance between the structure and the bottom of the ladder. In general, the base should be around 1/4 that of the height. For this example, the base will be just shy of 1/4 at 4.75 feet.

Finally, calculate the ladder angle using the formula above:

LA = atan(H/B)

LA = atan(20/4.75)

LA = 76 .639 degrees