Arctan Calculator - Inverse Tangent (arctan)

Your details

Choose how to supply the input. "Tangent value" is the standard mode. "Rise and run" computes the slope angle from two sides of a right triangle. "Reverse" finds tan(angle).
The value whose arctan you want. Can be any real number, positive or negative.
Arctan (degrees)
45deg

The inverse tangent expressed in degrees, between -90 and 90.

Arctan (radians)0.785398rad
Arctan (fraction of pi)pi/4
Tangent value used1
45 deg>99.9% below · x (tangent value)

arctan(1.0000) = 45.0000 deg

  • arctan(1.0000) = 45.0000 degrees = 0.785398 radians.
  • The result is positive (first quadrant, 0 to 90 degrees).
  • arctan always returns a value strictly between -90 and 90 degrees (-pi/2 to pi/2 radians).

Next stepTo verify: take tan(45.0000 deg) and it should equal 1.0000 (within rounding error).

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