The 900mg dosage on the jars is a milligrams dosage, which equates to about 2.7g of powder or roughly 1tsp. Based on this 1tsp dosage there are roughly 38 servings of in the 100g jar. However, 1/4 tsp once or twice a day is a great starting dose. You can build up from there. Consistency is key with tonic herbs, be sure to take them daily.