Bluetooth tracker range: what walls, bags and metal do

Bluetooth tracker range is not a distance you either have or do not have. It is a budget: the transmitter starts with a fixed amount of signal, and everything between the tag and your phone spends some of it. When the budget runs out, the link drops. Thinking about it that way explains why the same tag reaches the bottom of the garden but not the garage twelve metres closer, and it tells you exactly what to do about it.

The budget, and what spends it

A coin-cell tag transmits at a very low power — it has to, because it runs for years on a battery you could balance on a fingertip. From that starting point, three things consume signal.

Distance itself. Even in a vacuum, signal spreads out and weakens with the square of the distance. This is the loss you cannot design away.

Absorption. Materials that contain water — masonry, plaster, timber, a human body, a full rucksack — soak up energy at 2.4 GHz. The wavelength there is around 12 centimetres, which happens to interact enthusiastically with water molecules. That is not a coincidence; it is the same physics your microwave uses.

Reflection. Metal does not absorb much. It bounces the signal, which is worse, because a reflected signal is one that never arrives. A steel toolbox, a car body, a foil-backed insulation board or a metal filing cabinet can wipe out a link that would happily have crossed twice the distance through brick.

Roughly what each obstacle costs

The figures below are installers' rules of thumb rather than certified measurements, and they vary hugely with construction, moisture content and angle. Use them for ranking, not for arithmetic.

Two entries deserve a note. A person is worth more attenuation than most people expect — if a tag seems to drop out, turning around so your body is not between phone and tag sometimes brings it straight back. And angle matters: a signal crossing a wall diagonally passes through far more material than one crossing it square on, which is why range through the same wall differs depending on where you stand.

Bluetooth tracker range in a real house

In practice, most British homes are comfortably inside the working envelope. A tag in the kitchen answers from the top bedroom in a standard two-storey house. A tag in the hall answers from the end of a typical garden. The link tends to fail in specific, predictable places rather than gradually:

• An integral garage with a concrete floor above it and a metal door.
• A cellar with a concrete slab between it and everything else.
• A detached shed or garage across the garden with a metal roof.
• Anything inside a car parked on the drive.
• A loft where the insulation is foil-backed.

If your tag lives in one of those, you are not fighting the product. You are fighting a wall.

Placement rules that buy signal back

1. Get it off the metal. A tag lying on a steel surface performs far worse than the same tag five centimetres above it. Under a foam insert, in a lid pocket, or on a strap.
2. Height helps. A tag at waist level clears more clutter than one at floor level, and floors are among the worst obstacles in a building.
3. Keep it out of the middle of a full bag. The bag's own contents count as absorption.
4. Avoid the fridge, the microwave and the router. All three are noisy neighbours in the same band, and the fridge is a metal box.
5. Hold the phone up and away from your body when you are trying to reach a distant tag. It costs nothing and often works.

Is it a weak tag, or a bad spot?

A quick diagnosis, in order:

1. Put the tag on a table in the same room and ring it. If it does not respond, the tag or the cell is the problem — try a fresh CR2032 before anything else.
2. If it responds, walk to the far end of the house and try again. Failure here is a building problem, not a tag problem.
3. Take both outside into the open and walk away in a straight line. If you get a long, clean range outdoors, the hardware is fine and everything you saw indoors was attenuation.
4. If outdoor range is also poor, check the cell, then check the case has not been damaged or fitted loosely after a battery change.

Nine times out of ten this ends at step three, and the honest conclusion is that the tag is behaving exactly as specified in a building that is unkind to radio waves. The broader picture of what happens once the link genuinely drops is covered in our guide to how far a Bluetooth tracker works.

How BlueTag is specified for this

BlueTag quotes up to 60 m / 200 ft for the direct Bluetooth link, and that figure is a line-of-sight measurement in the open, stated as such rather than implied to be a household guarantee. Indoors you will get a fraction of it, and that fraction is still enough to cover a normal house and garden — which is where things actually get lost.

Two design choices help. The buzzer is 80–100 dB, so once you are inside the link you are following a sound rather than a signal-strength bar, and sound goes through soft furnishings that radio struggles with. And past the Bluetooth link entirely, the Apple Find My network takes over: the tag keeps broadcasting a rotating anonymous identifier, and any passing Apple device reports an encrypted position that only your Apple Account can read.

The shell is 36.3 mm on each side, 9 mm thick and about 10 g, sealed to IP67, with a moulded key ring hole and a CR2032 cell rated for a couple of years. Apple only: iPhone or iPad, iOS 14.5 and up, with no Android equivalent of this tag. Tags come two at a time, delivery within the UK costs nothing, and the price stays under £15 a box — see the full specification.