There are three kinds of tons: Metric, long, and short. I'm not sure which one you are looking for, but here are the conversions for all three:
There are 1016046.9088 grams in a long ton, 1000000 grams in a metric ton, and 907184.74 grams in a short ton.
I used this website to figure it out: www.asknumbers.com/tonnes-to-grams.aspx