"Off the scale" & "off the charts" - Whats the difference?

[hemantg]

If possible, please give a simple example illustrating the difference b\w the two.

[Tdol]

There's no difference for me.

[karu_bottlefingers]

scale is a form of measure, chart is a form of displaying information (in reguards to measurement in this case). so when someone says it's of the scale they are unable to measure it, an wen it is off da charts the measurement is not listed as it is too great. well that is my oppinion o nthe matter, may be right ... may b wrong. hope that this helps!!!

[moggy]

I agree with the definition of "Off the scale" but suspect that "Off the charts" has more to do with marine charts (maps) Something that is off the chart is unknown territory.
NB! This is only an opinion...I'm not 100% sure but as a sailor, my instincts say I'm right.