Gauge chart?

Hi, Could anyone tell me if there is such a thing as a gauge chart ?
What I mean is if a pattern reads: 12 st =4 inches with 8mm needles and a ball band reads 13 st =4 inches with 7mm how would I know it would work?
Of couse I’m talking about yarn substitution here, also these sizes are only an example.
Thank you,

I don’t know of a chart, but if the ballband gauge is close to the pattern gauge, you can usually substitute. That’s what the dreaded swatch is for.

I usually go by weight, worsted, dk, etc.

The label gauge is to tell you the weight of the yarn - DK, worsted, bulky - and they fall into a range. You can certainly try using the yarn in that pattern, it seems to be a similar weight. Here’s a chart http://www.yarnstandards.com/weight.html that may help you.