How Loud Is Too Loud? Measuring Noise With Your Phone
Nobody plans to damage their hearing. It happens gradually, at volumes that never felt dangerous at the time — a long drive with the windows down, a few hours of headphones a day, a gym with the music up, a hobby involving a power tool.
The reason it sneaks up on people is that the decibel scale is deeply unintuitive.
Decibels are not a normal scale
A decibel is logarithmic. That means:
- +10 dB is roughly twice as loud to your ear.
- +3 dB is double the actual sound energy hitting your eardrum.
So 90 dB is not “a bit more than” 80 dB. It carries ten times the energy, and the safe exposure time drops accordingly. This is why “it wasn’t that loud” is such an unreliable instinct.
The numbers worth memorising
Roughly, on the A-weighted scale that hearing-safety guidance uses:
- 30 dB — a quiet bedroom at night.
- 60 dB — normal conversation at a table.
- 70 dB — a busy restaurant, a vacuum cleaner. Annoying, not damaging.
- 85 dB — heavy city traffic from the pavement, a food blender. This is the threshold.
- 95 dB — a motorbike, a loud bar, headphones at high volume.
- 105 dB — a nightclub or a concert crowd.
- 120 dB — a siren at close range, a jet at takeoff. Immediate risk.
The trade between loudness and time
The important part isn’t the number on its own — it’s the number multiplied by how long you sit in it. The widely used guideline is that 85 dB is safe for about eight hours, and every 3 dB above that halves the safe time:
- 85 dB — about 8 hours
- 88 dB — about 4 hours
- 91 dB — about 2 hours
- 94 dB — about 1 hour
- 100 dB — about 15 minutes
- 106 dB — about 4 minutes
That last line is the one that surprises people. A loud gig is well past a safe daily dose within the opening song. This is exactly why musicians and sound engineers wear earplugs, and it is not because they are precious about it.
How to actually measure it
Your phone has a microphone, which means it can give you a usable reading of your surroundings — enough to tell 70 dB from 95 dB, which is the distinction that matters.
To get a reading worth trusting:
- Take the case off, or at least don’t cover the mic. Blocking it will read low.
- Hold the phone at arm’s length, roughly at ear height. Held against your body it reads low; pointed at a speaker from ten centimetres it reads high.
- Let it settle for 10–15 seconds. Sound levels fluctuate constantly, so a single instant tells you very little. Watch the range.
- Don’t measure in wind. Wind across a microphone produces enormous meaningless numbers.
- Treat it as an indicator, not a calibrated instrument. A phone mic isn’t a certified sound level meter, and it is optimised for voice. It will not stand up in a workplace dispute. It is entirely good enough to tell you that your gym is running at 100 dB.
Speaker Cleaner includes a noise meter alongside its tone tools, so you can check a room without installing something separate. It needs microphone permission — on iOS that’s Settings, Privacy, Microphone.
Things worth measuring at least once
- Your headphones. Play them at your normal listening level, then hold the phone right up to one earcup in a quiet room. The result surprises most people.
- Your commute. Metro carriages and bus engines routinely sit in the 80s and 90s.
- Your gym or your usual bar. If you have to raise your voice to be heard by someone at arm’s length, you’re likely above 85 dB.
- Anything with a motor. Hairdryers, blenders, drills, and lawnmowers cluster around 90–100 dB.
What to do with the number
You don’t have to live in silence. You have to notice the loud things and shorten them:
- Use the 60/60 rule for headphones — no more than 60 percent volume for no more than 60 minutes at a stretch.
- Carry cheap foam earplugs if you go to gigs. Modern filtered plugs cut level without muffling detail.
- Step outside for a few minutes every hour in a loud venue. The break genuinely counts.
- Take ringing ears seriously. Temporary tinnitus after a loud night is a sign that something was overloaded, not a fun souvenir.
Hearing loss does not heal. The hair cells in your inner ear do not regenerate, which is why every piece of advice here is about prevention rather than fixing. Measuring your own environment once in a while is the cheapest possible insurance.
