Karen

How do I convert mg (miligrams) or grams to teaspoon measurements? This is for a powder. Thanks

I need help on how to Convert Gallons of powder into lbs.

Karen,
A teaspoon like a gallon is a unit of volume and a mg. like a lb. is a unit of weight.
Just like a scoop (a given volume) of sand weighs more than a scoop of ground pepper or backing soda weighs more than flour without knowing what the powder you are using (or the specific gravity of your powder) there is no way to convert between the two.
The specific gravity is a comparison of how much more or less a given volume
of something weighs than the same volume of water. (for gasses use air)

Don