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ATAN Function (OpenOffice Calc)

Math Intermediate OpenOffice Calc Introduction not established

The ATAN function in OpenOffice Calc returns the arctangent (inverse tangent) of a value, in radians. Learn syntax, domain behavior, examples, and best practices.

Verification status: Consult the documentation, examples and any stated test scope below. How formula examples are checked

Availability and version history

  • Introduced: Documented by Apache OpenOffice 4.1.16; original introduction not established.
  • Availability: Supported in Apache OpenOffice 4.1.16, verified against its function registry. This identifies a supported release, not a final working version.
  • Scope: Desktop Calc, using the English function name. Availability in other spreadsheet applications is separate.
  • Checked: 2026-10-14 — function reference; versioned support. Documentation/source check; not a new native test. Existing example-specific test claims below retain their stated scope.

The ATAN function in OpenOffice Calc returns the arctangent (inverse tangent) of a value. The result is an angle in radians whose tangent equals the input. ATAN is essential for geometry, physics, engineering, slope calculations, and any situation where you need to convert a ratio into an angle.

What the ATAN Function Does

  • Returns the angle whose tangent equals the input
  • Output is in radians
  • Input can be any real number
  • Useful for slopes, rotations, and inverse trig calculations
  • Works across sheets

ATAN is ideal when you need to convert slope ratios into angles.

Syntax

ATAN(number)

Arguments:

  • number — Any real number (positive, negative, or zero)
ATAN returns an angle in radians.
Convert to degrees using:
ATAN(x) * 180 / PI()

Range of Output

ATAN returns angles in the range:

[ -\frac{\pi}{2} \le \text{atan}(x) \le \frac{\pi}{2} ]

This means ATAN cannot determine the quadrant — for that, use ATAN2.

Basic Examples

Arctangent of 1

=ATAN(1)

Result (radians): 0.785398163
Equivalent to 45°.

Convert to degrees

=ATAN(1) * 180 / PI()

ATAN using a cell reference

=ATAN(A1)

Convert slope to angle

=ATAN(Slope)

Advanced Examples

Angle of a line from rise/run

=ATAN(Rise / Run)

Convert slope to degrees

=DEGREES(ATAN(Slope))

ATAN across sheets

=ATAN(Sheet1.A1)

ATAN in array formulas

=ATAN(A1:A10)

Confirm with Ctrl+Shift+Enter.

Compute angle of a vector (2D)

=ATAN(Y / X)

(But ATAN2 is preferred.)

Convert angle back to slope

=TAN(ATAN(A1))

Always returns A1.

Use ATAN for smooth easing curves

=ATAN(t)

Use ATAN for asymptotic growth modeling

=A * ATAN(B * x) + C

ATAN vs ATAN2

Function Input Handles Quadrants? Typical Use
ATAN(x) One ratio (y/x) ❌ No Slope → angle
ATAN2(y; x) Two coordinates âś” Yes Vector angle

If you need the true direction of a vector, use ATAN2.

Common Errors and Fixes

ATAN returns Err:502 (Invalid argument)

Occurs when:

  • Input is text
  • Input is empty
  • A malformed reference is used

ATAN returns unexpected results

Possible causes:

  • Forgetting that output is in radians
  • Using degrees without converting
  • Using ATAN instead of ATAN2 for vectors

ATAN ignores values you expected it to include

ATAN ignores:

  • Text numbers ("123")
  • Empty cells
  • Logical values
  • Errors

ATAN includes values you expected it to ignore

ATAN includes:

  • Dates
  • Times
  • Numeric results of formulas

Err:508 — Missing parenthesis

Usually caused by:

  • Missing )
  • Using commas instead of semicolons

Best Practices

  • Use ATAN for slope‑to‑angle conversions
  • Use ATAN2 for vector angles or quadrant‑aware calculations
  • Convert radians to degrees when needed
  • Use named ranges for slope and coordinate values
  • Pair ATAN with TAN for reversible transformations
ATAN is perfect for slopes — ATAN2 is perfect for directions. Use each where it shines.