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How to Choose and Use a Level

From the basic bubble model to high-tech laser gadgets, here’s what you need to know about how to choose and use the right level for your project.

Photo by Kevin O’Connor

What is a Level Tool Used For?

A level is a tool used to determine whether a surface is horizontal (level) or vertical (plumb). Without this, you can't build a house that works well or looks good—not to mention hang kitchen cabinets or trim out a door.

The most basic such tool is a spirit level, which indicates level and plumb with a bubble inside a liquid-filled vial. At the high-tech end are laser levels, which project perfectly level or plumb lines onto a surface. Laser tools are great for layout work, but their fleeting lines aren't much help when you have to physically check the positioning of an object. For that, you need a tool with a bubble vial, which can rest on your workpiece or butt up against it. Only then can you be sure your work is on the level.

How to Calibrate a Spirit Level

For a level to do its job, it must be well calibrated. To check a spirit level:

  • Simply set it on a flat surface and note where the bubble ends up.
  • Then, flip the level end over end. If the tool is accurate, the bubble should fall in exactly the same place.
  • Levels with replaceable vials can be adjusted. Otherwise, throw away the bad level, or at least tape over the offending bubble.

Basic Spirit Levels

Crick Wood Level

What Are The Outer Lines For?

Many spirit (also called bubble) level vials have two sets of lines. When the bubble is centered between the inside pair, it indicates level.But when it touches one of the outer lines, it means the level is pitched at a 2-percent grade (about ¼ inch per foot of run), the slope required for waste lines, sidewalks, and rain gutters to drain properly.

Types of Specialty Levels


Photo by Laura Johansen

What are Torpedo Levels For? Small jobs like hanging pictures and shelves, or working in tight spaces, as when doing plumbing installations.

How Torpedo Levels work: Vials, visible from front or top, can show both level and plumb. Some models have magnets for sticking to metal pipes; this one has a built-in light to make reading the bubble easier.

Shown: Stanley lighted 9-inch torpedo level, $20 Amazon

Bull’s-Eye Level

Circular level

What is a Bulls-Eye Level For? Leveling an appliance or piece of furniture.

How does a Bulls-Eye Level Work? Level rests on piece; adjust legs or sides of piece until bubble is centered.

Shown: UBEI Aluminum Alloy Circular Bubble Level; $14 Amazon

2-Foot I-Beam Level

Photo by Laura Johansen

For: General-purpose leveling—hanging pictures and shelves, installing cabinets and rain gutters, or plumbing posts. Too short for decks, walls, trim, or concrete slabs.

How it works: Lightweight level butts against objects horizontally or vertically, with vials for level and plumb.

Shown: Stanley 24-inch FatMax level; $26 Amazon

4-Foot Level

Photo by Laura Johansen

For: Precision carpentry across a long expanse, as when installing cabinets, trim, doors, or floors. Plastic models are suitable for rougher work on gutters, drains, concrete slabs, and masonry walls.

How it works: Lengthy tool can span long distances, unaffected by bumps and dips. Curved vials are more accurate, but only the bottom one in the pair indicates level at any given time.

Shown: Crick Tool Co. 48-inch wood level; about $120;

Plumb Bob

Photo by Laura Johansen

For: Finding a point vertically above or below another point, as when positioning columns, building stairs or decks, or aligning framing.

How it works: By gravity—once fixed to a spot, the sharp-pointed weight hangs perfectly plumb on the string. This one attaches to the wall with a built-in punch pin.

Shown: Tajima Plumb-Rite; about $40 Amazon

Post Level

Photo by Laura Johansen

For: Setting posts and columns plumb.

How it works: Sides wrap around corner of post and show level in two directions, denoting plumb; magnetic models are good for positioning plumbing waste lines.

Shown: Johnson post level; about $6 Amazon

Laser Chalk Line Level

Crossline laser level

For: Establishing a level reference line for trim, cabinets, tile, shelves, or pictures.

How it works: Held up to a wall or fixed in place, tool projects level or plumb laser lines (or both); some units are self-leveling, and some include a stud finder.

Shown: SKIL Self-Leveling Red Cross Line Laser; about $60 Amazon

Rotating Laser Level

Rotating laser level

For: Large renovation projects that include laying out forms, installing floors or wainscoting, building walls plumb and square, or sloping walks, driveways, or gutters.

How it works: Self-leveling turret unit sits on floor or on tripod and shoots two rotating laser beams, one vertical and the other horizontal.

Shown: Topcon RL-H5A Self Leveling Horizontal Rotary Laser; $600 Amazon