My half-teaspoon measuring spoon fits perfectly inside the opening of a standard spice jar. Not theoretically perfectly, with no space between the two, but practically perfectly, with just enough room that I can put the spoon inside and scoop out some of what is inside.

As a result, I measure nearly all spices in half-teaspoons. If the recipe calls for a tablespoon, that’s six half-teaspoons. If it’s any more than that, I might start pouring from the jar into a larger measure instead.