There’s a reason why the hook at the end of a Lufkin tape measure isn’t in a fixed position. It wiggles on its rivets so it can make up for the hook’s thickness. When you push the tip against something for an inside measurement, the hook will be included in the reading. And when you hook it onto the end of a piece for an outside measurement, the gap will be equivalent to the amount of space the hook would take up. If the hook leaves you guessing when you’re measuring shorter distances, line up the 1-inch mark at the start and subtract that extra inch from the final measurement.