If you’ve ever browsed earplugs or earmuffs on our site, you might’ve come across something called SLC80. But what does it mean—and how does it help you choose the right hearing protection?
Let’s break it down.
The Quick Definition
SLC80 stands for Sound Level Conversion 80%, and it’s an Australian/New Zealand standard (AS/NZS 1270:2002) for measuring the effectiveness of hearing protectors.
In simple terms, the SLC80 rating tells you how much noise a product can block for 80% of users, under test conditions. It’s a way to compare earplugs, earmuffs, and other protectors on a level playing field.
How SLC80 is Calculated
During lab testing, a group of people wear the hearing protection, and the amount of sound reduction is measured across different frequencies. The SLC80 number is calculated by taking the average attenuation and subtracting a margin of safety to account for differences in how real people wear and fit their gear.
So when you see something like:
SLC80 = 25 dB
It means that 80% of users can expect the hearing protection to reduce noise by about 25 decibels—assuming a good fit.
What Does the SLC80 Number Mean in Practice?
Here’s a rough guide:
| SLC80 (dB) | Protection Class | Recommended Use Case |
|---|---|---|
| 10–13 | Class 1 | Low noise (e.g. office) |
| 14–17 | Class 2 | Moderate noise (e.g. public transport) |
| 18–21 | Class 3 | Factory or noisy urban areas |
| 22–25 | Class 4 | Loud worksites, power tools |
| 26–30+ | Class 5 | Heavy industrial, mining, gun ranges |
SLC80 vs NRR vs SNR 👂
If you’ve shopped internationally, you might also see NRR (Noise Reduction Rating) or SNR (Single Number Rating). These are the US and European standards, respectively.
They all aim to do the same thing—help you understand how much noise protection a product provides—but they use different test methods, so the numbers don’t translate exactly. As a general rule:
- SLC80 is most relevant in Australia and New Zealand.
- SNR is common in Europe.
- NRR is used in the United States.
How to Use SLC80 When Choosing Hearing Protection
When you're shopping for earplugs or earmuffs, consider:
- Your environment: Use the table above to match the SLC80 to your noise level.
- Comfort and fit: Even the best-rated protection won’t work if it doesn’t fit well.
- Type of sound: Low-frequency rumbles (like engines) vs high-pitched sounds (like alarms) may require different styles of protection.
Tip: If you're in extremely loud environments, pairing earplugs + earmuffs can provide extra safety—but make sure it's not so quiet you can’t hear alarms or communication.
In Summary
SLC80 is a key safety rating for hearing protection in Australia. It helps you compare products and understand how much noise they’re designed to block. Whether you're trying to sleep through snoring, focus in a noisy office, or stay safe on a job site, knowing the SLC80 rating can help you choose the right protection for your ears.