Arcus Tangent (arctan) Calculator

Your details

Normal mode: enter a tangent value and get the angle. Reverse mode: enter an angle and get the tangent.
Choose whether angles are shown (and entered in reverse mode) in degrees or radians.
The tangent value for which to find the angle. Accepts any real number.
Angle
45deg

arctan(x) expressed in degrees

Angle0.785398rad
Tangent value1
sin(angle)0.707107
cos(angle)0.707107
45 deg78.4% below · arctan(x) in degrees

arctan(1) = 45.0000 deg

  • arctan(1) = 45.0000 degrees (0.785398 radians).
  • arctan(1) = 45 degrees: this corresponds to a right triangle where the opposite and adjacent sides are equal.
  • The result lies strictly between -90 and 90 degrees (-pi/2 and pi/2 radians), which is the principal value range of arctan.
  • sin(45.0000 deg) = 0.7071, cos(45.0000 deg) = 0.7071.

Next stepFor right-triangle problems, arctan gives you the angle when you know the opposite and adjacent side lengths: arctan(opposite / adjacent) = angle.

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