8 Bad Measuring Habits You Should Drop

Updated: Oct. 27, 2023

Consistently making bad cuts and wasting material? A bad measuring habit may be the cause. Learn about mistakes you may not know you're making.

Taking accurate measurements is a fundamental skill every woodworker or DIYer, whether amateur and professional, must master. Success in almost every other skill is dependent on this core proficiency.

Unfortunately, there are some common bad habits you may unconsciously develop that can lead to poor measurements and bad cuts. That means wasted time, wasted money and a whole lot of frustration!

Here are some of the most common bad measuring habits and how you can break them.

Bending the Tape for Inside-to-Inside Measurements

Inside-to-inside dimensions (like the inside of a window frame) can be challenging to accurately measure. The habit of bending the tape measure into the corner and “eyeballing” the measurement can lead to inaccuracies.

Instead, incorporate the width of the tape measure’s base into your measurement. Many tape measures have their base’s width printed on them, with three inches being the most common. Instead of rolling the tape into the corner, get into the habit of adding the width of the tape measure’s base to the measurement instead.

Trusting Factory Edges

Too many woodworkers assume the end of the board they’re cutting (AKA the factory edge) is perfectly square. Consequently, they measure for cuts without verifying that’s actually the case. Depending on the width of the lumber and how out of square the end is, measuring off the edge can lead to inaccurate measurements.

Correct this by routinely checking the factory edge with your speed square. If the edge is out of square, use a miter saw or circular saw to cut a square edge prior to measuring. Although this extra step isn’t essential for many rough-framing tasks, it can make a big difference in making precise measurements for finish carpentry projects.

Trusting a Tape Measure’s Hook

Using your tape measure before inspecting its metal hook can cause you to inadvertently take inaccurate measurements. A tape measure’s metal hook is naturally loose by about 1/16th of an inch. They’re designed this way to obtain accurate measurements regardless of whether it’s hooked onto or butted up against the material being measured. Unfortunately, this also makes it susceptible to damage, which can make it less accurate.

Get in the habit of inspecting the hook prior to use. Alternatively, consider “burning an inch” to skip the hook entirely. To do this, use the one-inch mark as the “0” point instead of the hook and add one inch to the final measurement.

Not Writing Measurements Down

Routinely attempting to memorize measurements instead of writing them down can waste a great deal of time and perfectly good lumber. Forgetting your measurements will force you to repeat them, and misremembering can result in a bad cut.

Consider placing a sticky note on the back of your tape measure to remind you to write down your measurements. You may also want to keep a small notebook in your toolbelt or pocket to make writing down your measurements easy and convenient. Or just grab the nearest piece of scrap wood. Another option is to point at the correct measurement and snap a picture.

Marking Measurements With a Straight Line

Although not technically a poor measurement habit, marking your measurements with a single straight line can skew the accuracy. After all, a measurement used for cutting is only as good as the mark the cut is made on. Replace your straight lines with a “V” mark instead, with the point being your mark location. This is called a “crow’s foot,” and is standard marking practice among professional carpenters.

Using a Dull Pencil

Again: Your measurements are only as good as the marks the cuts are made on. Habitually using a dull pencil can result in a mark that’s too wide for the fine measurement tasks of finish carpentry. This is especially true when using a carpentry pencil, but can also apply to standard pencils. To correct this, sharpen your pencil before you start any measuring and several times throughout the day. Or, stick with the mechanical version.

Holding the Tape Too Loose and Crooked

Holding a tape measure taut and straight against the surface you’re measuring is imperative for obtaining accurate measurements. Without realizing it, you may be holding the tape at a slight angle, or with some slack in the tape that could impair accuracy.

Only Measuring Once

The old adage “measure twice; cut once” may seem obvious, but only measuring once before a cut is one of the worst (and most common) habits contributing to inaccurate measurements. Make this your motto and watch your success in measuring accurately soar. As a sacrosanct principle among carpenters, measuring twice should be seen as the bare minimum.