% formula

does anyone know what formula i have to use to workout a percentage

If you mean number format, it would be either:
0% or 0\% (depending if you want literal or not)

The number divided by 100

or one cell divided by another

or ... more details

A/B*100 or, A/B and format the cell as percentage

I usually use A/B-1, then format it as a %.
Also you can use the Text function to format it for you:

=Text(A/B-1,"0.0%")

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