ja, they say its 14% B, but that's for the decahydrate of sodium tetraborate. If using the anhydrous form, one gets nearly double the amount if calculatd using the 14% figure so you have to know what you're dealing with compositionally before making any calculations. Oops, I'm talking about boron here, sorry I don't mean to derail the topic, but same is true for anything one is measuring out.