What common objects, that most of us carry around much of the time, measure about 6 inches in length and about 2.5 inches in width?

If you have a billfold in your pocket or purse, you're carrying several precisely measured items. All modern U.S. banknotes, from the one-dollar bill to the one-hundred-dollar bill, share the exact same dimensions: 6.14 inches long by 2.61 inches wide. This uniformity makes them a surprisingly reliable, if unofficial, ruler for quick, approximate measurements when you're in a pinch.

This specific size has been the standard for nearly a century, but it wasn't always this way. Before 1929, U.S. currency was significantly larger, earning the nickname "horse blankets." The Treasury Department reduced the size of the notes by about 30% to lower manufacturing costs, as the smaller size allowed them to print more notes per sheet. This "small-size" currency has been the standard in the United States ever since.

Beyond their size, the material of these bills is also unique. They aren’t made of regular wood-pulp paper but rather a special blend composed of 75% cotton and 25% linen. This textile composition gives the currency its distinct feel and, more importantly, its impressive durability. A single bill can be folded back and forth thousands of times before it will tear, a necessary feature for an object that passes through so many hands.