The ordinary tape measure is the most commonly used measuring tool in the world, but for those just starting out, knowing how to read a tape measure might require a little explanation.
Used by professionals on the jobsite, amateur handypersons, and artists, measuring tape is an easy tool to use and, once you understand how it all works, an easy tool to read as well. In this guide to reading a tape measure, we’ll break down the most common measurement system, how to use it, and other ways to find or calculate different measurements.
The Measurement System – The Numbers on a Measure Tape
The measurement system you’re most likely to see and use to measure the length of your projects is known as the Imperial Measurement System or just Imperial. Feet and inches are most common on measurement tools such as the retractable steel tape pictured above. Even in countries that officially adopted the metric system of centimeters and meters decades ago, you’ll find a strange mix of both, with the Imperial System still being far more common for the applications readers of this article are likely to encounter.
Understand the Numbers on a Tape Measure, Ruler, or Measuring Stick – Feet & Inches
The largest and most visually dominant numbers on measuring tapes are inches. Inches are the best number to use when relaying information related to measurements for woodworking or to keep track of your own work. Every 12 inches there will be a number representing feet (written “1F’ here). It’s easier to avoid using feet if you’re finding precise measurements. Stick to inches and feet, as well as fractions of an inch as your chosen units of measurement.
The Whole Numbers – Inches
We start by reading the closest black number and rounding it down. If our measurement lands directly on 9, it is 9 inches. If the measured length lies between 9 and 10, we start with the lower number, 9, and add the fraction.
The Fractions – Half of an Inch
Fractions of an inch are used when the measurement doesn’t land exactly on one of the lines marked for inches. The easiest to find is half. Whle inches will be measured with the longest or a complete line, half will be marked by the second longest line and it is, you guessed it, halfway between each number.
Possible Variations: 1/2″
Quarters of an Inch
Quarters are the next longest lines and can measure lengths between the half inches. They divide the halves in half creating four equal lengths. This is the hallmark of measuring in the imperial system using a tape measure, splitting the previous increment in half. We’ll see this trend continue.
Possible Variations: 1/4″ or 3/4″
Why isn’t there a 2/4″? You’ll notice where 2/4″ would be is actually 1/2″, a measurement to that point remains 1/2″.
Eighths of an Inch
Just like the quarters split the halves in half, eights divide the quarters by two. Eights are the next longest line after quarters on your tape measure.
Possible Variations: 1/8″, 3/8″, 5/8″ or 7/8″
Sixteenths of an Inch
If you’re into measuring with sixteenths then we need to be friends. Measuring in sixteens is very accurate and may not even appear on some tape measures. When they are there, they’ll be the shortest line, halfway between each eighth line.
Possible Variations: 1/16″, 3/16″, 5/16″, 7/16″, 9/16″, 11/16″, 13/16″, 15/16″
Even Smaller Increments
You’re not likely to use anything beyond sixteenths of an inch but it is possible to continue this trend on to thirty-seconds, sixty-fourths and so on.
The Red Numbers
Why are some numbers red or in red blocks? Some tape measures will have these extra or stylized numbers, in our example the manufacturer has used red. The red blocked numbers are every 16 inches. This is relevant in home building as most walls, floors, and rafters are spaced at 16 inches. If you’re framing a house you already know this, but this could come in handy if you’re building a small deck, a garden shed or looking for multiple wall studs to hang a shelf. The red numbers here are inches beyond the previous “foot” measurement. In this example, the red “3” indicates: 1 foot and 3 inches.
The Floating Hook or Tang
You’ll notice the metal end of your tape measure is loose or floating. That is because when you place it on the outside of an object and pull on the tape to measure, the hook will slide out slightly so true zero is now the edge of your piece. When you’re measuring an inside dimension, like a window frame, the metal bit pushes back just a little making ‘zero’ the outside, or in this case, the window frame.
Finding the Middle of Something
What if you need to find the middle of something? For example, cutting a peice of wood exactly in half or trying to hang a painting in the middle of a run of wall. To do this you’ll need to divide your full measured length in half. Sounds easy, but is it? Here are two quick tricks.
Finding the Middle Trick #1
Using two tape measures, pull the tape across from both sides. Find where the numbers are the same, that is the middle. This works great for smaller measurements.
Finding The Middle Trick #2
Another trick: find a loose measurement and round up to the nearest whole inch that you can easily divide by two. For example, 65 ¼ can become 66 or even 70. Now, place the end of your tape measure on one side, pull the tape at a diagonal until you can line up 70 with the other side. Half of 70 is 35 so we can now find 35 and mark it as the middle. In this photographed example, we rounded 4 1/4″ to 5 and marked on an angle at 2 1/2″ (5 divided by 2) to find the middle of our board, 2 1/8″
Finding the Middle For Math Geniuses
As easy and reliable as the methods above are, some people like to exercise their minds and find the middle the old fashioned way: Math, but not actual hard math. To do the math quickly and easily, I like to separate the whole number from the fraction, divide both by 2 and add them back together. Wait, what?
Step One – Divide the Whole Number
Let’s work through it using this example where we are looking for the centre of this wall that measures 43 3/4”. First, divide the whole number by 2. This is pretty easy for most numbers but there is no shame in pulling out the calculator app for this one if it’s a large or odd number. 43 divided by 2 is 21 1/2. But what about that 3/4 we left off?
Step Two – Divide the Fraction
We can’t forget about that 3/4”. 21 1/2 plus 21 1/2 is only 43, we need to bring that 3/4 back into our calculation to truly find the middle. Just like we found half of 43, we need to find half of 3/4 and add in back in. This is actually easier than you think. All we have to do is double the bottom number. Sounds too good to be true? It’s not. Half of 3/4 is 3/8. It’s that easy.
Combining our Two Calculations
Now that we have two calculations, 21 1/3 and 3/8 we need to add them together. How do we do that? There is a mathematical method to do this and create one proper number, but it’s complicated so we’ll just avoid that. Simply find 21 1/2 on your measuring tape, now slide 3/8 past that point and voila! You’re in the middle. 21 7/8!
Other Measuring Tools – Laser Measurement Device
If you find yourself measuring a lot of large spaces, you might want to invest in a laser measurement device or a tape/laser combination. More expensive versions of his device can even do some of the math for you.
Measuring Long Distances
You can use the laser measurement device to measure long distances but there are still old-fashioned tools to measure long distances. These tools will come in handy for activities like planning a garden or buying material for a fence.
Tools for Measuring Long Distances
Two widely available tools for measuring long distances are a Reel Tape Measure and a Measuring Wheel. The reel will work just like a regular tape measure and determine the distance along a straight line between two points. The measuring wheel is great if you’re working alone and need to measure curves and around corners but its accuracy will be affected by dips and bumps.
Courtenay Hartford is the author of creeklinehouse.com, a blog based on her adventures renovating a 120-year-old farmhouse in rural Ontario, Canada. On her blog, Courtenay shares interior design tips based on her own farmhouse and her work as founder and stylist of the interior photography firm Art & Spaces. She also writes about her farmhouse garden, plant-based recipes, family travel, and homekeeping best practices. Courtenay is the author of the book The Cleaning Ninja and has been featured in numerous magazines including Country Sampler Farmhouse Style, Better Homes and Gardens, Parents Magazine, Real Simple, and Our Homes.