How to Choose a Sound Level Meter
For checks at home, a Class 2 meter with A and C weighting, fast and slow response and a max hold covers almost everything. Pay for Class 1, logging and a calibrator only when someone else has to trust your numbers.
First: do you need one at all?
Try the free decibel meter first. If you only want to know whether a room is louder than last week, or whether your headphones are pushing past 85 dB, a phone or laptop will tell you. NIOSH researchers found 4 of 10 shortlisted phone apps stayed within ±2 dB of a professional meter, and the iOS apps did better than Android. Buy a meter when you need the same reliable number every time, or a number you can show someone.
What to look for
| Feature | What it does | Who needs it |
|---|---|---|
| Class 2 | General-purpose accuracy under the IEC 61672 standard | Home, hobby, most checks |
| Class 1 | Tighter tolerances under the same standard | Formal, legal or professional work |
| A weighting | Follows human hearing; used in most noise limits | Everyone |
| C weighting | Keeps more low-frequency sound; used for peaks and bass | Music, bass, machinery |
| Fast / Slow | Fast reacts in 125 ms, Slow averages over 1 s | Everyone; Slow is easier to read |
| Max hold | Keeps the highest reading on screen | Short, loud events |
| Data logging | Saves readings over time, often to a computer | Long or overnight measurements |
| Calibrator | Plays a known level so you can check the meter | Anyone who needs to trust the number |
Class 1 vs Class 2 in plain words
The international standard for sound level meters, IEC 61672, sorts them into Class 1 and Class 2. Both measure the same things. Class 1 has to stay accurate across a wider range of frequencies and conditions, so it costs more. Older US meters use the ANSI names Type 1 and Type 2 for roughly the same split. A cheap meter that lists no class at all can still be handy for rough checks; just do not expect its numbers to be accepted by anyone else.
Range and resolution
Check the lowest level the meter can read. A quiet bedroom at night can sit near the bottom of a cheap meter's range, and a meter that cannot read that low will show its floor instead of the real level. At the top end, make sure the range covers what you are measuring: concerts and power tools go well past 100 dBA (see the levels in how loud is too loud).
What it costs
Prices vary a lot. One price comparison of 11 meters with US prices, dated August 2026, ran from $25.99 to $559, with a median of $114. The low end covers basic handheld meters; the high end adds logging and better class ratings.
Use it properly
- Hold it at arm's length, pointed at the source, away from your body, which reflects sound.
- Use the foam windscreen outdoors or near fans.
- Check it with a calibrator before important measurements, if you have one.
- Write down the setting you used (A or C, Fast or Slow) next to every reading.
Questions
- Do I need a Class 1 or Class 2 sound level meter?
- Class 2 is enough for home, hobby and most general checks. Class 1 has tighter tolerances and is what acousticians use for precision and formal work. If someone else (a lawyer, a regulator, a client) will rely on the number, ask them which class they accept before you buy.
- How much does a sound level meter cost?
- One August 2026 price comparison of 11 US-priced meters ran from $25.99 to $559, with a median of $114. Cheap meters are fine for rough checks; class-rated meters with logging cost more.
- Is a phone app as good as a sound level meter?
- Sometimes close. NIOSH testing found 4 of 10 shortlisted phone apps stayed within ±2 dB of a professional meter, and an external calibrated microphone brought that to about ±1 dB. A dedicated meter is more consistent from device to device and easier to calibrate.
- What is the difference between A and C weighting?
- A-weighting follows human hearing and is used for most noise limits. C-weighting is flatter and keeps more low-frequency sound, so it is used for peak levels and for bass-heavy noise.