Use a spirit level properly
10 mins to learn — used in nearly every DIY job
A spirit level is one of the most-used tools in DIY — and one of the most misused. Reading it correctly and checking its accuracy takes two minutes. Getting it wrong makes every shelf, tile row, and fixture look visibly off.
Last updated: March 2026
Only basic tools needed — most homes already have them.
Before you start
This guide covers using a standard bubble spirit level — the most common type, available from £5 upwards. Digital levels and laser levels work differently, but the principles (what 'level' and 'plumb' mean) are the same.
For most jobs in a house, a 600mm level is the right length. Short levels (under 300mm) accumulate error over long distances. A 1200mm level is useful for tiling and skirting boards.
Keep your level stored flat — leaning against a wall for months can warp cheaper plastic levels and affect accuracy.
Some links on this page are affiliate links. If you buy through them we may earn a small commission at no extra cost to you.
Tools & materials
- ✓Spirit level (600mm minimum)— longer is better for horizontal reference lines — a 1200mm level is ideal
- ✓Pencil— to mark reference lines as you go
Want everything in one go?
Prices shown on retailer sites. Always check current pricing before purchasing.
Understand what the bubble is telling you
A spirit level contains one or more vials — small curved tubes filled with liquid and a bubble of air. When the bubble sits exactly between the two black lines marked on the vial, the surface is level (horizontal) or plumb (vertical). If the bubble is to the left of centre, the left end is low. If it is to the right, the right end is low. The vial in the middle of the level reads horizontal. If your level has a vial at 90 degrees to the main body, that reads vertical (plumb). Why: reading the bubble correctly sounds obvious but is often done from the wrong angle. You must look at the vial directly from above or straight on — viewing from an angle gives a false reading.
Most people get this done in under 5 minutes.
Where beginners go wrong
Reading the bubble from an angle. You must look at the vial directly from above (for horizontal) or straight on (for vertical). Viewing from even a slight angle shows the bubble in a different position to where it actually is.
Not checking the level's own accuracy first. A dropped or cheap level can be inaccurate. Flip it end-for-end and check the bubble is in the same position. If it has moved, do not trust the level for precision work.
Using a short level for long reference lines. Extending a horizontal line across a full wall with a 300mm level accumulates small errors at each step. Use the longest level you have, or a laser level for rooms wider than 3 metres.
Following the existing wall or floor instead of a true level. Old houses have floors and walls that are out of level by 10–20mm over a few metres. Always work from a true level reference, not from the existing surface.
When a spirit level is not enough
Setting out a tile layout across a full bathroom or kitchen — use a laser level to project a horizontal line across the whole room at once
Checking if a floor is level before laying engineered wood or laminate — lay the level in multiple directions across the full floor area, not just at one point
Setting out a large outdoor project like decking or a patio — a water level (a long tube filled with water) gives accurate readings over long distances
Recommended starter kit
Five tools that cover most home repairs.
- →Adjustable spannerAmazon·Screwfix
- →Screwdriver setAmazon·Screwfix
- →PTFE tapeAmazon·Screwfix
- →Spirit levelAmazon·Screwfix
- →Tape measureAmazon·Screwfix
Want everything in one go? Get it on Amazon
What you just learned
You know how to read a spirit level correctly, verify its accuracy, mark horizontal reference lines, and check for plumb. These skills are used in almost every practical DIY task — shelving, tiling, picture hanging, fitting radiators, and bathroom installation.
This unlocks: