When all else fails, go to "Joy of Cooking" --see "equivalents and or substitutions, and I quote:
1 Tsp raw ginger = 1/8 tsp pwd. This info is usually on the spice container, but I
use a less expensive brand and it does not have the info. cmg
1/4 teaspoon of ginger (dry powder) to 1 Tablespoon of fresh ginger you grate.
Avoid doing this. The proportions unbalance a recipe when you substitute ground for freshly grated ginger.
It is a spice
A one inch piece of fresh, grated ginger (generally yielding 1 tablespoon) equals approximately 1/8 teaspoon ground (dried) ginger. Source: http://www.evitamins.com/healthnotes.asp?ContentID=3602003
1 inch of ginger grated will produce about 4 teaspoons.
Ginger (Fresh) 1 tablespoon, grated or chopped equals a 1-inch piece
1 tablespoon fresh rosemary equals 1 teaspoon dried
Dry is always more potent, as long as your spices are not old. If you have "fresh" dry ginger, 1 teaspoon would be the right amount to substitute for 2 tablespoons of fresh ginger. Since ginger is something that loses its potency in dry form very quickly, the best possible answer to this question is "to taste."
No amount of dried ginger equates to any amount of fresh finger; they have two completely different flavors and they will never behave the same in any recipe. Powdered ginger has a deeper, smokier, spicier flavor we know from gingerbread, gingersnap cookies, etc... Fresh ginger is sharp, bright, slightly lemony and even biting. Don't attempt an exchange, no matter what anyone tells you. It won't work.
Ground ginger can NOT be substituted for crystallized ginger--that is something quite different. Otherwise, you are fairly safe to use ground, minced, and grated ginger interchangeably unless the ginger is being used for garnish purposes (sushi, for instance). The thing to remember is that ground ginger is exponentially more potent than fresh ginger. Ultimately it comes down to a matter of personal taste, but I rarely use more than a few pinches of the ground stuff.
1/8 to 1/4 teaspoon of ground ginger for every 1 tablespoon of fresh ginger Start with the smaller amount (1/8 teaspoon) and taste your mixture. If you find that you want a stronger ginger flavor, you can gradually add more, up to 1/4 teaspoon, but be cautious not to overdo it, as ground ginger can quickly become overpowering. Keep in mind that the substitution may slightly alter the texture of your beauty DIY recipe, as fresh ginger adds some moisture, while ground ginger is dry. Adjust the consistency as needed by adding a small amount of water or another liquid to your mixture if necessary.
Stem ginger is taken fresh and preserved in sugar syrup. It has a different taste than root ginger which is usually allowed to dry somewhat and is grated or ground and put in to dishes and also a very famous cola #1.
I would just use the same amount because ginger paste is basically really finely miced ginger. Maybe cut down a slight amount if your not a huge fan of ginger.