There are some pretty standard items that you can use if you don’t have a ruler handy to measure something. Most of them are standard sizes, such as a sheet of paper measuring 8.5″ × 11″ so it will fit into most computer printers with ease. Here are a few of the best ways to do a quick measurement (remember, too—some of these are approximations):

• A sheet of standard letter paper is 8.5 by 11 inches long.
• U.S. paper currency measures 6 1/8 inches wide and 2 5/8 inches long.
• Most standard business cards measure 2 inches long by 3 ½ inches wide.
• Most postcards measure 3 inches by 5 inches.
• The diameter of a quarter is about one inch; the diameter of a penny is approximately 3/4 of an inch.
• A credit card is about 3 3/8 inches by 2 1/8 inches.
• A standard AA battery is about 2 inches long.
• The average adult toothbrush is about 7 inches long.