How to Figure Angles for Horizontal Ceilings

A protractor measures the degrees of an angle.

Calculating angles is a necessity for homeowners installing trim inside their homes. This problem has been overcome by a simple tool called an angle finder. The angle finder is based on the design of a protractor. Most modern angle finders are digital, so you won't need to read markings; you'll only need to read numbers on a screen. An angle finder is a necessary tool when you are working in houses, because even if your house has a horizontal ceiling, it is very unlikely that your ceiling is true or exactly horizontal. It is very common for walls, ceilings and floors to be off by one or several degrees.

Things You'll Need

• Angle finder

Instructions

1. Open the angle finder. Most angle finders are about 8-inches long and they have two arms emerging from a rounded end. The finder opens by sliding the two arms apart.

2. Position one arm of the finder against the wall, and the second arm against the ceiling. Press so that each arm is flat and snug to the surface. Lock the angle with the angle lock. Turn on the digital display.

3. Read the digital display. The display will identify the true angle of the two surfaces. Most angle finders have a range of 225 degrees, and they often have a level built into the handle, so you can see whether the surface you are measuring is level or approximately level. Because the angle is locked, you can take your angle directly to the miter saw when you are cutting trim.

Tips & Warnings

• Turn your display off when you aren't using the tool to save the battery.