When I first started Dunn DIY, I really didn’t know much about working with tools. I approached them with so much caution that projects took me twice as long as they should have, and I wasn’t getting the full use out of my tools. In Tools 101, I’m sharing everything you need to know about tools so you can DIY with confidence.

A level is a simple tool that’s invaluable when it comes to setting posts or mounting shelves. Although it’s not something I use in most of my DIY projects, it is something I find very useful for being a homeowner (or, in my case, an apartment occupant). 

When to use

First and foremost, levels are used to make sure things are correctly angled. In general, this means finding level (the horizontal plane), plumb (the vertical plane, or perpendicular), and 45° angles. A level can be used to put together that perfect gallery wall of photos, but I find it most important when it comes to more permanent structures, like hanging a headboard, shelving, or a wall-mounted desk. Not to mention its use for backyard projects like setting posts and building fences. Levels can also be used to check level and plumb on household appliances being installed. 

For more advanced users, levels can be used to measure the slope of countertops and cabinets, for leveling decks, and for building houses. For now, though, we’ll stick to the basic uses.


For the most part, levels are rectangular objects outfitted with one or more liquid vials. Inside the vial, the bubble is what’s used to measure angles. When the bubble is centered in the vial, the angle is correct. Depending on the direction of the vial within the tool, the bubble will measure level, plumb, or 45°. Or some levels have adjustable vials that can be set to any angle.  

Longer levels are more accurate than shorter levels because they cover more area, but the length you want is also dependent on the size of your project. You don’t need a 3’ level to hang an 8” x 11” picture frame.

Some levels have magnets for mounting to metal surfaces. These magnets can also conveniently be used as a sweep to pick up loose screws and nails. Higher quality levels have rubber ends to protect the level if dropped. And if your level has a hole on one end, you can hang it from a nail when it’s not in use.

Best practices

The number one rule of levels is don’t drop your level! Your level may not look damaged after a short drop, but the impact of the drop could throw off the accuracy of its reading. 

To test whether the accuracy of your level has been compromised, lay it on a flat surface and place sheets of paper under one end until you get a level reading. Then, flip the level around and test to see if you get the same reading with the opposite end on top of the paper. If you do, the level is accurate.

Types of levels

Torpedo levels are small levels ideal for tight spaces and smaller projects. They’re easy to carry and store, and they generally vary in size from 6” to 12”. This is a great level for keeping in your tool bag.

Box beam and I-beam levels are fairly similar to each other. Both types are larger than torpedo levels, and longer levels are generally more accurate than shorter levels. Box beam levels are sturdier, more durable, and less likely to become inaccurate over time than I-beam levels. I-beam levels weigh less than box beam levels and are more affordable. Both of these longer levels are perfect for working with larger projects or for projects where perfection is important.

Line levels hook onto a piece of string and work well to set fence posts or fence boards at the same height. Be careful, though: Even with the string stretched taut, there’s always a slight bit of sag, so this type of level isn’t for extreme accuracy.

Post levels are two-sided levels that attach to vertical structures like fence posts, flagpoles, railing posts, and even fridges to measure level in multiple directions at once. They can be secured around a wood fence post with a rubber band and often have magnets to attach to metal posts. 

Cross-check and bull’s eye levels are smaller levels designed to sit on a flat surface. Cross-check levels find level in two perpendicular directions at once, while the circular bull’s eye levels check level in all directions at once.

Our recommendations

Torpedo levels are great for beginners. They’re small and easy to use, and they’re really all you need for living in an apartment or to build smaller projects.

If you’re a homeowner or growing your toolkit, a 24” to 36” level is a good standard size. The larger size will provide enhanced accuracy for bigger projects.

Line levels and post levels aren’t tools you’ll use regularly, but if you’re building a fence, these are the way to go.


If you don’t have a level for mounting something on a wall, you can measure up from the floor or down from the ceiling in several places—as long as your floor or ceiling isn’t visibly slanted.

You can also use an app on your smartphone to find what’s level.

With any substitution, though, remember to use your eyes first and foremost. If it doesn’t look level to you, it’s probably because it isn’t!

Whether you’re a beginner, are growing your tool kit, or are building something that requires a little more finesse, a level is the best way to make sure your work is straight and sturdy. For more practice with tools, check out our posts on how to use a tape measure, how to use a square, and how to use sandpaper.