Levels

Torpedo

For: Small jobs like hanging pictures and shelves, or working in tight spaces, as when doing plumbing installations. How it works: 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 magnetic torpedo level; about $9; homedepot.com

Bull’s-Eye

For: Leveling an appliance or piece of furniture. How it works: Level rests on piece; adjust legs or sides of piece until bubble is centered. Shown: Sears Craftsman circular level; about $1.50; sears.com

2-Foot I-Beam

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; about $22; amazon.com

4-Foot

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; cricktool.com

Plumb Bob

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; acetoolonline.com

Post Level

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: Sears Craftsman post level; about $5; sears.com

Laser Chalk Line

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: Black & Decker Crosshair laser level; about $58; sears.com

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: Porter-Cable rotational level from Robotoolz; about $600; amazon.com

What Are The Outer Lines For?

Many spirit-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. Making Sure A Level Is 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.