I can’t believe I had difficulty with this one for so long:

=MOD(450-*angle*,360)

This assumes you’re measuring the angle in the usual Cartesian way; anticlockwise from the x-axis.

I can’t believe I had difficulty with this one for so long:

=MOD(450-*angle*,360)

This assumes you’re measuring the angle in the usual Cartesian way; anticlockwise from the x-axis.

It appears that the same formula can be use to convert from a bearing back to an angle: =MOD(450-bearing,360). But I could be wrong.