The TAN function calculates the tangent of an angle provided in radians. If your angle is in degrees, you must multiply it by PI()/180 or use the RADIANS function to convert it.
=TAN(RADIANS(45))→1Calculates the tangent of 45 degrees by converting it to radians first.
Select a cell
Click on the cell where you want to display the result.
Enter the formula
Type =TAN(number) and replace 'number' with your angle value or cell reference.
Ensure your input is in radians. Excel's trigonometric functions expect radians, not degrees.