How Far Does Wi-Fi Actually Reach Indoors?

The box said 300 feet. Your back bedroom is 40 feet from the router and it buffers. Nobody lied to you — that number was measured outdoors, in a straight line, with nothing in between, and your house is not that.

Here are the distances Wi-Fi actually covers inside a home, why the loss is so front-loaded, and a short piece of arithmetic that turns your own layout into a usable radius.

Reach is two different distances#

Ask "how far does Wi-Fi reach" and you get two answers, several times apart.

The first is where a device still connects. Phones will hold an association down to about -85 dBm, which is the level where the link is technically alive and practically useless. The second is where Wi-Fi still works: around -67 dBm, the practical floor for reliable video and voice. What each level supports is set out in the dBm scale and what it buys you.

That gap matters more than it sounds. Roughly 18 dB separates the two, and 18 dB is three doublings of distance — so the radius where your phone still shows a network can be several times the radius where the network is worth having. It is the whole explanation for a device that shows bars in the garage and cannot load a page.

One asymmetry gets forgotten: your router transmits with more power and better antennas than your phone, so its voice carries further than your phone's reply. Coverage is limited by the weaker half of that conversation, and a strong reading on the screen never proves the router can still hear you.

Marketing distances describe the first radius, outdoors. A claim of 2,000 square feet of coverage is that same figure drawn as a circle, assuming the square footage is empty. Treat both as a physics ceiling, not a prediction about your hallway.

Every doubling of distance costs about 6 dB#

Radio energy spreads out over the surface of an expanding sphere. Double the radius, and that surface is four times bigger, so the energy landing on your phone's antenna is a quarter of what it was. A quarter of the power is 6 dB. That is the inverse-square law, and it is the only equation you need.

Two things fall out of that table, and both are counterintuitive.

The loss is front-loaded. Walking from 5 feet to 10 feet costs you exactly as much signal as walking from 40 feet to 80 feet. The first room is expensive; the far end of the house is cheap.

Past the first room, distance stops being the story. Crossing an entire average house in open air might cost you 20 dB. One brick wall can cost 16 dB on its own. That is why counting feet ranks people's houses badly and counting obstacles ranks them well.

Real indoor decay is steeper than the table, because floors, furniture and people absorb as well as obstruct — though reflections sometimes carry signal down a hallway better than free space would. The 6 dB rule is a planning tool, not a guarantee.

Honest indoor numbers, by band and construction#

These are the radii at which a typical client still reads roughly -67 dBm or better, in an average home, with the router out in the open. Treat them as rules of thumb.

The band column is a trade, not a ranking: 2.4 GHz goes furthest and carries least, 6 GHz is the reverse, and the reasoning is laid out in which band reaches which room. If your home is in the bottom two rows, the numbers get harsh quickly and the fixes are different — see Wi-Fi in brick and concrete homes.

Vertically, the answer depends entirely on what the floor is made of. A timber floor with joists typically costs 6 to 12 dB, so the room directly above the router is usually fine and the far corner of that floor usually is not. A reinforced concrete slab costs 15 to 25 dB, which in practice ends the conversation: the floor below or above needs its own access point regardless of square footage.

One wall is worth a lot of feet#

Because 6 dB equals one doubling of distance, you can convert any obstacle straight into feet. A wall that costs 6 dB has the same effect as moving twice as far away. A wall that costs 12 dB is the same as moving four times as far.

Halve those figures roughly for 2.4 GHz, which is why the smart plug in the garage keeps working while the laptop two rooms away does not. Doors, joisted floors, coated glazing and foil-backed insulation all have their own conversion, and the full per-material breakdown — including how the angle you hit a wall at changes the number — is in signal loss by building material.

Work out your own usable radius#

Ten minutes with a phone and this list gives you a number for your house rather than for a house in a brochure.

1. Work on 5 GHz. It is the band your laptops, phones and TVs actually use, and it is the one that runs out first.
2. Take a reference reading about 10 feet from the router with clear line of sight. Expect something between -30 and -45 dBm. Android exposes this in the Wi-Fi network details; on an iPhone, read your own device's signal from the router's admin page instead.
3. Set your floor at -67 dBm. Below that, calls and streams start failing.
4. Subtract to get your budget. A reference of -40 dBm leaves 27 dB to spend before you hit the floor.
5. Spend the walls first. Draw the straight line from the router to the room that matters and subtract each obstacle it crosses using the table above. One stud wall at 5 dB and one brick wall at 13 dB leaves 9 dB.
6. Convert what is left into distance. Divide the remainder by 6 to get doublings, then double your 10-foot reference for each one. Nine dB is 1.5 doublings, so 10 ft becomes about 28 ft.
7. Compare that with reality. If the room is 45 feet away along that line, it was never going to work, and now you know it before buying anything.
8. Repeat for the worst path, not the friendliest one. Coverage is judged by the seat that fails.

Pad the answer by 3 to 5 dB before you trust it. Signal wanders that much on its own while you stand still, and furniture, doors and people all take their cut. If you would rather measure than calculate, the walk-test and grid methods are in how to map Wi-Fi coverage.

When the house is bigger than the radius#

This is where the honest answer disappoints people: you cannot meaningfully buy more reach from a single router.

A better antenna that adds 3 dB buys about 1.4x the distance in open air, and one drywall wall erases it. Routers already transmit close to the regulatory ceiling, so a "long range" model is mostly marketing on the same power budget — and raising the router's output only widens the range at which your phone hears a network it is too weak to answer.

The fix for a house bigger than one radius is another radio closer to the problem. As a rule of thumb, plan one access point per 1,000-1,500 sq ft in open, timber-framed construction, and one per 700-1,000 sq ft in brick, block or plaster. Every floor counts as its own zone.

An extender has to sit inside the working radius, not at the edge of it: put it where the router still reads -60 to -67 dBm, as covered in how far an extender can sit from the router and the placement walkthrough. Some rooms placement cannot rescue. If the target is 80 feet away through two masonry walls, no outlet lets an extender both hear the router properly and reach the room — any spot close enough for one is too far for the other. That is a job for a cable or a mesh node on a wired backhaul, not for a better guess about where to plug something in.

Getting the radius before you walk it#

Steps 5 and 6 are arithmetic, so software can run them for every point in the house at once instead of one path at a time. That is what Range Up does with a floor plan: you trace the rooms, set the material preset to stud or block to match how the place is built, drop the router on its real spot, and the radius stops being a single number and becomes a shape that bulges down the hallway and stops at the chimney. Multi-floor plans get the same treatment in a 3D view, which is where the floor loss value earns its keep.

It is a simulation, not a meter — it does not measure your live network or scan for anything — but for "how far will this reach", a prediction you can sanity-check against one real reading beats walking the house with a phone. Model your own layout before you buy hardware that may be solving the wrong problem.