ATAN2
Return the angle, in radians, from the origin to a point, taking the x and y coordinates separately so the quadrant is correct.
Syntax
ATAN2(x_num, y_num)| Argument | Required | Description |
|---|---|---|
x_num | Required | The x coordinate (horizontal). |
y_num | Required | The y coordinate (vertical). |
Examples
Every example below was executed against VisiGrid engine 0.51.0 — not
transcribed from another vendor's documentation. Reproduce any of them with vgrid calc.
| Formula | Result | Notes |
|---|---|---|
=DEGREES(ATAN2(1,1)) | 45 | |
=DEGREES(ATAN2(-1,-1)) | -135 | Down and to the left. ATAN of the ratio would say 45. |
=DEGREES(ATAN2(-1,0)) | 180 | Straight left. |
=DEGREES(ATAN2(0,1)) | 90 | Straight up — a run of zero, which ATAN cannot express as a ratio. |
=ATAN2(0,0) | #DIV/0! | The origin has no direction. |
x first, then y
Spreadsheets put the arguments in the opposite order from most programming
languages. In Python, JavaScript, C and Rust it is atan2(y, x); here, as in
Excel, it is ATAN2(x, y). Swapping them does not error — it gives the angle
measured from the other axis, which is plausible enough to go unnoticed.
The range is -180 to 180
ATAN2 returns between -π and π — -180 to 180 degrees — measured anticlockwise
from the positive x axis. For a compass-style 0 to 360, add a full turn to the
negative results:
=IF(ATAN2(-1,-1)<0,DEGREES(ATAN2(-1,-1))+360,DEGREES(ATAN2(-1,-1))) → 225Excel compatibility
Matches Excel, including the x-then-y argument order and #DIV/0! at the origin.