For precision crafts such as quilting and woodworking, it pays to keep a ruler or measuring tape on hand. However, for many other crafts -- from miniatures to scrapbooking to certain knitting or crochet projects -- you can make do with a close estimate. You can use parts of your body, items from your wallet or common household objects to gauge an inch fairly accurately.
Use Your Body
Crook your index or pointer finger; the bone between the first and second knuckles measures about an inch long.
Hold your thumb against the materials you're measuring. For most people, the thumb measures about an inch from tip to first knuckle.
Compare the width of your hand to your crafting materials. The width of the palm of your hand, right beneath the knuckles, is about 4 inches on most people -- so one-quarter of that distance would be 1 inch.
Check Your Wallet
Measure your materials against the short edge of your driver's license, credit card or just about any other rigid plastic card in your wallet. These cards are almost always standardized to measure 2 inches along the short edge, so half of that is 1 inch.
Use business cards instead. A standard business card also measures 2 inches along the short edge.
Fold a dollar bill in half the long way. In the United States, all modern paper currency -- dollar bills and any other denomination -- measures 2.5 inches by 6 inches. Folding it in half doesn't give you an exact inch, but at 1-1/4 inches, it's still a pretty close measure.
Other Household Objects
Check your index cards. Fold a 3-by-5-inch index card into even thirds along the long axis, and you have an accurate inch-long measure. Fold a 4-by-6-inch business card once along the long axis, then again along the same axis, to get an inch-long measure along the short end.
Empty out your piggy bank. The easiest coins to use for inch-long measurements are quarters -- which are 7/8-inch wide -- and nickels, which are 3/4-inch wide.
Check for other handy household objects that can help you approximate an inch. These include flat-headed thumbtacks, which are just over a 1/4 inch wide; tea light candles, which are about 1 1/2 inches wide across the bottom; and standard-size staples, which typically measure a 1/2 inch across the middle and a 1/4 inch along each side.