How to Convert Between Degrees and Radians in Excel

Excel’s trig functions work in radians. RADIANS and DEGREES convert both ways for ramps, roofs and solar panels.

You will learn to

• Convert degrees to radians
• Convert an angle from radians back to degrees
• Use RADIANS inside a trig formula

How it works

Excel’s trigonometry functions (SIN, COS, TAN, ATAN…) all work in radians, not degrees. RADIANS(angle) converts degrees to radians — =RADIANS(180) is π — and DEGREES(angle) converts back, so =DEGREES(PI()) is 180.

Two patterns cover most real work: wrap degree inputs in RADIANS before a trig function (=COS(RADIANS(30))), and wrap the result of an inverse trig function in DEGREES to read it (=DEGREES(ATAN(rise/run)) gives a slope angle in degrees).

=DEGREES(ATAN(C3/D3))