Record 10 seconds of sound in one place, then 10 seconds in another — and see which one is really quieter, by how much, and whether you'd actually hear the difference.
Tip: use the same device for both recordings and hold it the same way.
Values are averaged over each 10-second recording. Re-record either place any time — the result updates automatically.
Our ears are surprisingly bad judges of loudness. Walk from a busy kitchen into a bedroom and the bedroom feels silent — but measure both and the "silent" room might still be humming along at 45 dB thanks to a fridge behind the wall or traffic leaking through a window. Numbers settle arguments that impressions can't.
Comparing two rooms is genuinely useful when you're picking a spot for a home office or a baby's cot, deciding which bedroom faces away from the street, or checking whether the money you spent on sealed windows actually changed anything. Measure before and after, and you'll know.
To keep the comparison fair: use the same device for both recordings, hold it at roughly the same height and distance from walls, keep quiet while it records, and do both places within a few minutes of each other — a room at 8 am and the same room at 6 pm are two different rooms.
Decibels aren't a normal scale — every 10 dB roughly doubles how loud something feels to your ears, and means ten times more sound energy. So a room at 60 dB doesn't feel "a bit louder" than one at 50 dB; it feels about twice as loud. A 3 dB gap, on the other hand, is barely noticeable — that's why the verdict tells you whether you'd actually hear the difference.
Because the room changed, not the meter. Fridges cycle on and off, traffic comes in waves, a neighbour closes a door. A 10-second recording is a snapshot. If a room matters to you, record it at the time of day you'll actually be using it — a bedroom at midnight, an office at 10 am.
Don't — the comparison will lie to you. Microphones vary a lot between devices, easily by 10 dB or more, which is bigger than most real room differences. Both recordings on the same device, held the same way, is the one rule that matters here.
An instant reading catches whatever happened in that split second — a cough, a car horn, or an unusually quiet lull. Averaging over 10 seconds smooths those spikes out, so you're comparing what the rooms are typically like, not what they did in one lucky moment.
No. The audio itself is never stored — it's turned into loudness numbers on the fly and thrown away. Even those numbers only live in your browser tab; close or refresh the page and they're gone. Nothing is uploaded, ever.
It matters a lot — sound gets quieter fast as you move away, so holding the phone at your chest for one place and at arm's length for the other can invent a difference that isn't real. Pick one comfortable position — say, held still at chest height, screen up — and use the exact same distance and angle for both recordings. Consistency beats precision here: it's fine if the number isn't perfect, as long as both places were measured the same way.
Yes, that's one of the best uses for it. Record the room before the work, then record it again afterwards from the same spot at a similar time of day, with the same outside conditions (a quiet Sunday vs. rush hour will skew things). If the "after" reading drops by 5–10 dB, that's a genuine, audible improvement. A drop of just 1–2 dB is within normal noise and probably means the change didn't do much for that particular sound.
Not quite. Phone and laptop mics aren't calibrated instruments and can be off by ±10 dB from a professional meter, so treat the reading as a solid ballpark rather than an exact figure. Where this tool really shines is comparison — if two rooms or two times of day come out clearly different, that difference is real and dependable even when the absolute number isn't perfect.