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 (Review) 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.