dB Logger: Sound Level Meter

Free to download. One-time unlock. No subscription, ever.

dB Logger turns your phone into a professional-grade sound level meter, frequency analyzer and noise logger — with no account, no cloud, and no subscription, ever.

Most sound apps measure your phone's audio AFTER the operating system has "cleaned it up" with echo cancellation, noise suppression and automatic gain. dB Logger doesn't. It captures RAW, UNPROCESSED audio — from the built-in mic or an external USB-C measurement microphone — so what you see reflects the real acoustic field.

WHAT PEOPLE USE IT FOR
• Measure a noisy neighbor, upstairs bass, or HOA / tenant nuisance — log it over time and export a timestamped CSV + PDF report to attach to a complaint.
• Check whether a concert, gig, gym class, bar or restaurant is loud enough to risk your hearing — and how long is safe.
• Find out if your baby's white-noise machine is too loud at the crib, and how far to move it.
• Assess a room like a consultant: NR and NC single-figure ratings from octave bands for HVAC and building-services work.
• Track workplace noise exposure against OSHA, NIOSH or EU limits with the built-in dosimeter.
• Check a sound system, studio, AV install or science project with a live spectrum and weighted levels.

MEASURE
• Real-time dB-A, dB-C, dB-Z with selectable update rate (200 ms to 10 s)
• Fast / Slow / Impulse time weighting; current, AVG (Leq), MAX and PEAK
• NR (Noise Rating) and NC (Noise Criteria) single-figure room ratings
• A noise-source guesser that tells you WHAT is loud, not just how loud

VISUALIZE
• Live FFT spectrum, 20 Hz – 20 kHz, with peak-hold and peak detection
• 1/1 & 1/3-octave equalizer with per-band peak caps
• Scrolling time-history graph, color-coded by level
• A clean analog dB gauge with AVG / MAX / PEAK

LOG, REPORT & SHARE
• Log metrics to CSV and raw audio to lossless WAV, independently
• Browse saved sessions and generate PDF / CSV reports
• Noise Camera: snap a photo or record a video with the live dB reading burned in — clear evidence, easy to share

BUILT RIGHT
• Guided + manual calibration, saved per microphone profile
• USB-C external measurement-mic support, with a visible input picker so you always know which mic you are measuring with
• 42 languages; light / dark and Glass / Classic themes
• On-device and private — no account, no cloud; your audio and readings never leave your phone unless you choose to share them

FREE vs FULL VERSION
dB Logger is free to download and fully usable for live measurement — the meter, gauge, spectrum, spectrogram, analyzer and dosimeter are all free and unlimited. The free version also lets you record, export and film video for up to 30 seconds so you can try the whole workflow; those trial clips, exports and reports carry a small "Trial" mark, and the free version keeps two days of dosimeter history. Unlock the full version with a single one-time purchase — no subscription, ever — for unlimited recording, unlimited CSV/WAV/PDF export, full-length video with no watermark, the complete dose history, and no ads. Already bought "Remove Ads"? You're upgraded to the full version automatically, at no charge.

Accuracy note: a smartphone microphone is not a certified Class 1/2 (IEC 61672) sound level meter. dB Logger targets reproducible, calibrated relative measurement with standards-correct weighting and rating math. For regulatory or compliance decisions, verify with certified instrumentation.