It's a Snap! How to Snap a Line

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Put a perfectly straight line anywhere you need it with this simple contractor's tool

What is snapping a line, anyway? In this rare case in the world of DIY-ing, this is as simple as it sounds! Snapping a line involves making a straight line in chalk across a surface using a simple tool called a chalkline.

When Would I Want to Snap A Line?

Snapping a line comes in handy when you want to draw a perfectly straight line across the length of an entire surface that can be easily wiped away. We would use this when trying to find the center of a room, as a guide for laying out flooring, to provide an accurate straight line for cutting large pieces of lumber-anywhere you need to establish a perfectly straight line between two points. Typically, this technique is used for drawing an easy to remove, super-straight line quickly over a large surface.

The Tool

The chalkline reel looks similar to a tape measure. Inside, instead of a ruled piece of steel, you'll find a spool of chalky string, with a reservoir for chalk. A handle lets you spool up the string after you've made your mark.


Chalkline tools They come in two sizes, the smaller holds 50 feet of string and the other 100 feet. The Japanese adapted a version that uses ink instead; it's called a tsumitsubo. You want to use chalk because it's not permanent, though some colors can clean up easier than others.

Jane Tip: The reels come empty. You must add your own chalk, sold separately in a jug. The color you choose will depend on what you are doing. For instance, red chalk can bleed through drywall, so go with blue or white!

How to Use It

Step 1

To use a chalkline, measure and mark the two points you wish to connect. Then, simply hook the metal piece to one edge of the surface. Then, with the metal piece anchored in place, move to the other point to be connected, gently unspooling chalky string as you go. Keep some tension on the reel as you pull the string over to the second connection point.


Step 2

When you have the line lying flat and exactly where you want it, pull on the reel to make sure the line is taut, then lock the tool in place and lay it down.


Step 3

From the middle of the string, lift the chalky string in a straight line above the surface. Pull it up 3 to 5 inches, just enough to put moderate tension on it (a bit like drawing an arrow back on a bow). All at once, let it go with a snap!


Carefully lift the string from one end and reel it back into the case. The string should leave a straight, chalky line in its place.

Step 4

Unhook the string and reel it back into the tool. You've just laid down a straight, removable line.

See? We Told You It's a Snap

There you have it-snapping a line is simple and can serve you in so many ways. Now, if only laying tiles were as easy...

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