Use your PC as a decibel meter
Most people who search for a decibel meter for PC want an answer to a plain question: is this room too loud? Is the music next door over the limit, is the open-plan office wearing everyone out, is the workshop loud enough to need ear defenders? A dedicated sound level meter answers that, but you may not own one. Your laptop already has a microphone.
This app reads that microphone and shows the level on a drawing of a classic handheld meter, with an LCD-style display and keys you can actually press. It covers 30 to 120 dB. Each reading comes with a plain-language comparison underneath, such as 62 dB · Normal conversation, taken from a scale that runs from Quiet library at 30 dB through Light rain, Vacuum cleaner and Heavy traffic up to Thunderclap at 120.
Below the display sit the minimum, the average and the maximum for the last 10 minutes. The average is an energy average, the way a proper meter computes Leq, so a few loud bangs pull it up as much as they should.
How loud is too loud? Sound level meter zones
The meter changes color so you do not need to remember thresholds. It turns amber at 70 dB, around the level of a vacuum cleaner, and red at 85 dB, the point at which long exposure starts to put hearing at risk. For reference, eight hours a day at 85 dB is the commonly cited limit, and every few decibels above it shortens the safe time sharply.
If you want a nudge rather than a glance, turn on the noise alert and pick the level that matters for your room: 60 dB suits a study or a nursery, 70 dB an office, 85 dB a workshop or a rehearsal space. A brief spike is ignored; a room that stays loud gets a red plate on the meter, a Windows notification titled It is too loud in here, and a tray tooltip that reads Over 85 dB, or whichever level you chose.
A or C weighting, and calibrating a PC microphone
Press the weighting key on the meter, labeled Switch A or C weighting, to change how it listens. A weighting tracks human hearing and is right for noise complaints and hearing questions. C weighting keeps more bass and suits music, subwoofers and machinery.
Computer microphones are built for voices, not measurement, and Windows may apply its own gain, so treat out-of-the-box readings as estimates. To calibrate, borrow a meter and set it to the same weighting. Put both microphones side by side, about a foot from a steady sound such as a fan or a running tap rather than speech, and wait for the reading to settle. Choose Calibrate, type what the reference meter shows, and every reading from then on carries that correction. Recalibrate if you switch to a different microphone.
The other keys on the drawing do what they would on a real meter: hold the current reading, show the maximum, and switch on the backlight for a dim room.
Measure noise with your phone, read it on the PC
A desktop PC cannot be carried to the source of the noise, and a laptop on the windowsill is awkward to read. Press Measure with your phone, scan the code with the phone's camera, and the meter opens in the phone's browser. Tap Start the microphone and the phone's readings appear on the PC as they happen.
That split is the useful part. Leave the phone by the shared wall, at the speaker or next to the crib, and watch the level, the 10-minute maximum and the alert from your desk. The button changes to Phone connected while the link is live, and the phone keeps a calibration of its own.
