Rectangle Diagonal Angle Calculator

units
Enter length in units.
units
Enter width in units.
Math

Rectangle Diagonal Angle: calculate results from explicit inputs, with a formula and worked example.

Formula

angle to length side = atan(width/length)

Example Calculation

Example inputs
  • Length: 4 units
  • Width: 3 units

Length 4 and width 3 give an angle of approximately 36.8699° to the length side.

Frequently asked questions

How do I use this calculator?

Enter length, width. The result updates automatically. Use Reset to restore the example values.

What method does it use?

angle to length side = atan(width/length). Euclidean geometry. Use one consistent length unit; areas and volumes use its square and cube. Degenerate shapes are rejected. Very thin shapes may lose floating-point precision.

Why might a rounded result differ?

The calculation keeps full numeric precision internally, then rounds the displayed result. Rounding intermediate steps by hand can produce a slightly different answer.

Are my inputs saved online?

No. This calculator processes your inputs in your browser. A recently used list stores only calculator names on this device, not your entered values.

Check the assumptions and units before using this result. Read about calculation methods.