Returns the arctangent (inverse tangent) of a number, in radians. The result is an angle between -π/2 and π/2 (-90 and 90 degrees). Essential for trigonometry, engineering calculations, angle conversions, and solving equations involving tangent.
Master the fundamentals of Excel ATAN function
The ATAN function returns the arctangent (inverse tangent) of a number in radians. It is the inverse of the TAN function: if y = TAN(x), then x = ATAN(y). ATAN returns angles between -π/2 and π/2 radians (-90 to 90 degrees). Unlike ACOS and ASIN, ATAN accepts any real number as input. For determining angles from x,y coordinates with proper quadrant detection, use ATAN2 instead.
Returns angle whose tangent is the number
Accepts any real number (no range restriction)
Result is in radians (-π/2 to π/2)
Always returns -π/2 to π/2 range
Function-specific parameters
Function-specific return type
Find angles from tangent values
Calculate angles in engineering problems
Solve triangle angle problems
Calculate angles from slopes (use ATAN2 for full range)
Exact matching required
Returns numeric position
Handles missing text gracefully
=ATAN(number)The tangent of the angle you want. Can be any real number. The arctangent is the angle whose tangent is number.
The arctangent in radians (-π/2 to π/2, or -90 to 90 degrees)
Description: Returns the arctangent (inverse tangent) of a number in radians
Calculate arctangent
Returns approximately 0.785 radians (45 degrees). ATAN(1) = 45° because tan(45°) = 1.
Use ATAN function in VBA
' Basic ATAN in VBA
Range("C1").Value = Application.WorksheetFunction.Atan(1)
' Returns: 0.785 (radians)
' Calculate angle in degrees
Sub CalculateAngleDegrees()
Dim tangentValue As Double
tangentValue = Range("A1").Value
Dim angleRadians As Double
Dim angleDegrees As Double
angleRadians = Application.WorksheetFunction.Atan(tangentValue)
angleDegrees = Application.WorksheetFunction.Degrees(angleRadians)
Range("B1").Value = angleDegrees
End Sub
' Calculate angle in triangle
Sub TriangleAngle()
Dim opposite As Double, adjacent As Double
opposite = Range("A1").Value
adjacent = Range("B1").Value
Dim tangent As Double
tangent = opposite / adjacent
Dim angleDegrees As Double
angleDegrees = Application.WorksheetFunction.Degrees( _
Application.WorksheetFunction.Atan(tangent))
Range("C1").Value = angleDegrees
End Sub
' Use ATAN2 for full range
Sub UseATAN2()
Dim x As Double, y As Double
x = Range("A1").Value
y = Range("B1").Value
' ATAN2 determines correct quadrant
Dim angleDegrees As Double
angleDegrees = Application.WorksheetFunction.Degrees( _
Application.WorksheetFunction.Atan2(x, y))
Range("C1").Value = angleDegrees
End SubFind angle from tangent ratio
Convert tangent to angle in degrees
Calculate angle from slope (use ATAN2 for full range)
Calculate angles in engineering applications
ATAN only returns -90° to 90° range
Use ATAN2(x, y) for full 360° rangeSolution: ATAN returns -π/2 to π/2 range. For full 360° range with proper quadrant detection, use ATAN2(x, y) which returns -π to π range based on coordinates.
ATAN returns radians but need degrees
=DEGREES(ATAN(A1))Solution: Wrap ATAN with DEGREES: DEGREES(ATAN(number)). This converts radians to degrees. Remember: π radians = 180 degrees.
ATAN cannot determine correct quadrant
Use ATAN2(x, y) instead of ATAN(y/x)Solution: For coordinates, use ATAN2(x, y) instead of ATAN(y/x). ATAN2 determines correct quadrant and returns -π to π range.
ATAN results have many decimal places
=ROUND(DEGREES(ATAN(A1)), 2)Solution: Use ROUND for display: ROUND(ATAN(value), digits) or ROUND(DEGREES(ATAN(value)), digits) for degrees.
Uncertainty about ATAN vs TAN relationship
ATAN(TAN(45°)) = 45° (after converting)Solution: ATAN is inverse of TAN: ATAN(TAN(angle)) = angle (in radians, within -π/2 to π/2). TAN(ATAN(value)) = value.