How to Estimate Measurements Without a Ruler or Tape Measure

Illustration of items to measure things with

Illustration: The Spruce / Elise Degarmo

There are many easy ways to estimate measurements using parts of your body or items you may have on hand. This can come in handy when you are shopping to determine if an item is the proper size—wallpaper or fabric with a certain pattern size, for example. It is particularly helpful for scale model enthusiasts, such as model railroaders or dollhouse collectors, who are always on the lookout for interesting accessories for their hobbies.

Learn the lengths of some common body parts and ordinary objects, and use these to estimate the measurements of items.

Common Measurements Based on Your Body

Parts of your body can be used to estimate many common units of measurement. Obviously, people vary in size, so it's best to first measure your own body parts in order to understand how close your own proportions are to these averages. 

  • One inch (2.5 cm) is roughly the measurement from the top knuckle on your thumb to your thumb tip. Measure yours to see how close it is to 1 inch. After all, you should always have a thumb handy for a guide for measuring items under 6 inches (15cm)! In model miniatures, such as standard dollhouse scale (1:12), 1 inch is equal to roughly 1 foot.
  • Four inches (10cm), or one hand width for measuring horses, is roughly the width of most people's hands measured across your bottom knuckles (without the thumb).
  • One yard (36 inches or 92cm) is roughly the distance from your nose to the knuckle of your index finger (with your hand in a fist) on an outstretched arm. If you use this measurement often, measure your arm to see how close this measurement is to 1 yard.
  • One meter (39 inches) is a similar measurement to the yard above, but use your arm with fingers extended and measure to the tip of the fingers. This is an easy way to estimate yards and meters of cord, fabric, or ribbon. Check the length of your arm against a ruler or measuring tape to find out how close to 1 meter this distance is for you. 
  • One elbow length, or the distance from your bent elbow to the tips of your fingers, is 15 to 18 inches (35 to 48 cm) for most people.
  • A woman's size-9 foot (U.S. and Canada) is usually 10 inches (25 cm) long. In Europe, this is a size 40 and in the UK, size 6.5.

Measurements Based on Office Items

Ordinary items you have around your office or home desk have standard measurements that can be used to estimate the measurements of other items. ​

  • A standard business card is 3.5 inches long x 2 inches high (9 cm x 5 cm).
  • Standard credit and ID cards are 3.4 inches wide x 2.1 inches high (8.5 cm x 5.4 cm).
  • A standard sheet of printer paper is 8.5 inches x 11 inches.
  • Business envelopes are 4 inches x 9.5 inches.
  • A standard paper clip is 1 inch long; a large paper clip is 1.8 inches. 

Using Coins and Bills to Measure

Almost everyone carries a few bills or coins in their pocket, and knowing their dimensions can help you estimate measurements of other items.

  • A U.S. bill is 2.6 inches tall x 6.2 inches long (6.6 cm x 15.8 cm).
  • Canadian bills are 6 inches long x 2.8 inches tall (15.2 cm x 7 cm).
  • A 1-cent coin is .75 of an inch (2 cm) across.
  • A quarter is just under 1 inch (2.5 cm) across.
how to measure without a ruler
The Spruce

Standard Furniture Measurements

You can use these standard dimensions as the basis for estimating the rough size of larger items. And by converting the measurements, you can also use them when buying pieces of furniture or accessories for model buildings or dollhouses. The sizes below are the sizes of the real items: In 1:12 scale, for example, a six-foot (72-inch) door would be 6 inches tall (15 cm).

  • Standard modern doors are 78 to 80 inches (198 to 203 cm) tall.
  • A dining room tabletop is usually 30 inches (76 cm) above the floor.
  • The seat of a dining room chair is usually 15 to 17 inches (38 to 43 cm) above the floor.

Using Your Smart Phone

Not only can the physical phone itself serve as a unit of measure if you look up its dimension, but you may also find it offers apps that provide an actual ruler scale that lets you measure small items laid on the face of the phone.