How to Install Floating Shelves Perfectly Level

What Makes Floating Shelves Go Wrong

Most shelf installations fail at the same two points: the bracket holes aren't level with each other, and the wall isn't as flat or plumb as it looks. Both problems are easy to solve before the drill comes out — much harder to fix after.

The good news is that your phone's accelerometer is indifferent to both problems. It measures against gravity, not against the wall, so it tells you what's actually level regardless of what the room tries to suggest.

What You Need

Your phone with Bubble Level installed
A pencil
A tape measure
A drill with a masonry or wood bit appropriate for your wall type
Wall plugs and screws (usually supplied with the brackets)
A stud finder (for timber-framed walls)
The shelf and its brackets or hidden rod system

Step 1 — Decide on Position and Mark the First Bracket

Choose your shelf height and mark the position of the first (leftmost) bracket with a pencil. This is your reference point for everything else, so take a moment to get the height right before committing. Hold the empty shelf up against the wall at rough height and step back — it's much easier to adjust now than after you've drilled.

If your wall has studs (timber-frame construction), use a stud finder to locate the nearest stud to your first bracket position. Screwing into studs is significantly stronger than relying on wall plugs alone, especially for shelves that will carry books or other heavy items.

Step 2 — Mark the Second Bracket Using the App

This is where the phone saves you time and guarantees accuracy. Rather than measuring up from the floor (which may not be level) or across from the ceiling (which almost certainly isn't), you use the app to find true horizontal.

Lightly fix a thin batten or even a length of masking tape horizontally between the two bracket positions.
Place your phone flat along the batten or tape and open Bubble Level in flat mode.
Slide one end up or down until the app reads 0.0°. Mark both endpoints.
Remove the batten. Your two bracket marks are now on a true horizontal line.

Alternatively, if your bracket has a flat top face: fix the first bracket loosely, rest the shelf on it without the second bracket, place your phone on the shelf surface, and slide the free end up or down until the app reads 0.0°. Mark the second bracket position. This method is even faster.

Step 3 — Drill and Fix the Brackets

With both positions marked, drill your holes. For masonry walls, use a hammer drill and the correct masonry bit for your wall plug size. For timber stud walls, a standard wood bit is fine and you may not need plugs at all.

Don't fully tighten the screws yet. Get both brackets loosely in place so the shelf can rest on them. This allows you to make final small adjustments before locking everything down.

Step 4 — Final Level Check Before Tightening

Rest the shelf on both brackets (or slide it onto the hidden rods if it's that type of system). Place your phone flat on the shelf surface and check the reading.

If it reads 0.0° — perfect. Tighten all screws fully.
If it's off by a fraction — loosen the lower bracket slightly and add a thin washer or card shim behind it to push that side forward. Re-check.
For hidden-rod systems, the rods usually have a small amount of vertical play at the shelf end — use it to fine-tune before tightening the grub screws.

The goal is 0.0° or within ±0.2°. At that tolerance you won't be able to see any tilt by eye, and anything placed on the shelf will sit flat.

Step 5 — Check the Shelf is Plumb Front-to-Back

Floating shelves can also tilt forward or backward — either because the brackets are angled or because the wall surface is uneven. Rotate your phone 90° and hold it against the front face of the shelf, or rest it on the shelf pointing toward the wall, to check the front-to-back angle.

A very slight backward tilt (shelf sloping imperceptibly toward the wall) is usually desirable — it prevents lightweight items from sliding off. About 0.5° backward is ideal. Anything over 1° forward tilt and things will roll off.

Installing Multiple Shelves at Different Heights

For a stack of shelves — a bookcase-style arrangement on an open wall — the principle is the same for each shelf, but now consistency between shelves matters as much as individual accuracy.

Install and level the bottom shelf first, fully tightened.
Measure upward from the bottom shelf surface (not the floor) to mark the next shelf height. This keeps spacing consistent regardless of floor level.
Level each subsequent shelf independently with the app.
Once all shelves are in, do a final check by placing your phone across two shelves at once on a long straight batten to verify they're co-planar.

Hollow Walls and Plasterboard

On hollow walls you need to either hit the studs behind the plasterboard or use specialist cavity fixings (toggle bolts, spring toggles). The app plays the same role in both cases — it tells you where level is, regardless of the fixing method.

Weight warning: even the best cavity fixing in 12.5mm plasterboard should carry no more than 10–15kg per fixing point without hitting a stud. For heavy loads — books, a record collection, large plants — always find the studs or use a French cleat that spans multiple studs.

The French Cleat Alternative

If you want a shelf system that's adjustable without re-drilling, consider a French cleat: a length of timber with a 45° bevel ripped along its edge, screwed to the wall (spanning multiple studs for strength). Matching cleats on the back of each shelf hook over it.

To level a French cleat, use the app the same way: rest the cleat on the wall at the rough position, place your phone on its top edge, and adjust until you read 0.0° before marking the screw positions. Once a French cleat is level, everything hung from it is automatically level too.

Quick Checklist

Mark one bracket first, use the app to transfer the level to the second
Don't fully tighten until the shelf is in place and checked with the app
Target 0.0° side-to-side, 0–0.5° backward tilt front-to-back
For multiple shelves, measure spacing from shelf to shelf — not from the floor
Match fixing method to wall type and load