How to Use a Level Correctly

A level is one of the simplest yet most essential tools in any DIYer's kit. Whether you're hanging a picture frame, installing shelves, or laying tile, a level ensures everything is perfectly horizontal or vertical. Here's how to use one correctly every time.

Types of Levels

• Spirit/bubble level: The classic tool with liquid-filled vials. Available in 2", 9", 24", 48" and longer lengths.
• Digital level: Shows angle readings on an LCD display — more precise for angled cuts and installations.
• Laser level: Projects a laser line across a room — great for large-scale projects like tiling or hanging multiple items in a row.
• Line level: A small bubble level that clips onto a string line — used for outdoor grading and masonry.

Recommended Level

For precise angle measurements and both horizontal/vertical leveling, the Neoteck Aluminum Digital Angle Finder Protractor offers a 225° range with backlit LCD and dual bubble vials — perfect for DIY and professional use. Check it on Amazon →

Understanding the Bubble Vials

A standard spirit level has two or three vials:

• Horizontal vial (center): Used to check if a surface is level (perfectly horizontal)
• Vertical vial (end): Used to check if something is plumb (perfectly vertical)
• 45° vial (if present): Used to check diagonal angles

The surface is level or plumb when the bubble sits exactly between the two lines in the vial.

How to Check If a Surface Is Level (Horizontal)

1. Place the level on the surface you want to check.
2. Look at the center horizontal vial.
3. If the bubble is between the two lines — it's level. ✓
4. If the bubble is to the left — the left side is lower. Raise the left side.
5. If the bubble is to the right — the right side is lower. Raise the right side.

How to Check If Something Is Plumb (Vertical)

1. Hold the level vertically against the surface (a door frame, wall, or post).
2. Look at the vertical vial at the end of the level.
3. If the bubble is centered — it's plumb. ✓
4. Adjust until the bubble centers.

How to Use a Level for Hanging Items

1. Hold the item (shelf bracket, picture frame, etc.) against the wall.
2. Place the level on top of the item.
3. Adjust the item left or right until the bubble centers.
4. Mark the wall through the mounting holes while holding everything steady.
5. Remove the item and drill your holes at the marks.

How to Verify Your Level Is Accurate

Levels can lose accuracy if dropped. Test yours:

1. Place the level on a flat surface and note the bubble position.
2. Rotate the level 180° (flip end-to-end) on the same surface.
3. If the bubble is in the same position — your level is accurate.
4. If it shifts — your level needs calibration or replacement.

Tips for Better Results

• Use a longer level for larger surfaces — longer = more accurate
• Always read the bubble straight-on, not at an angle (parallax error)
• On rough surfaces, place the level on a straight board first
• For multiple items in a row, use a laser level or chalk line

Common Mistakes to Avoid

• Reading the bubble from an angle instead of straight-on
• Using a damaged or dropped level without checking accuracy first
• Using too short a level for large surfaces
• Not accounting for wall imperfections (use a straight board as a bridge)