STC to Rw
Type a value in STC to get it in Rw instantly.
That's 2.5× as quiet as a blockwork wall, while a party wall is 2.5× better. A 75 dB television next door would come through at about 26 dB.
Convert the other way: Rw to STC
What it means
How much sound gets through?
STC and Rw use different weighting curves, so the one-decibel offset is a good rule of thumb, not an exact conversion. Both ignore low bass, where walls perform worst.
The math
How to convert STC to Rw
The rating is a logarithm of what gets through: dB = −10 × log₁₀(transmitted fraction). STC runs about one decibel above Rw for ordinary partitions.
Example: 50 STC = 49 Rw.
Every unit
Your rating in every unit
Tables
STC to Rw conversion table
| STC | Rw |
|---|---|
| 20 STC | 19 Rw |
| 25 STC | 24 Rw |
| 30 STC | 29 Rw |
| 35 STC | 34 Rw |
| 40 STC | 39 Rw |
| 45 STC | 44 Rw |
| 50 STC | 49 Rw |
| 55 STC | 54 Rw |
| 60 STC | 59 Rw |
| 65 STC | 64 Rw |
| 70 STC | 69 Rw |
Rw to STC conversion table
| Rw | STC |
|---|---|
| 20 Rw | 21 STC |
| 25 Rw | 26 STC |
| 30 Rw | 31 STC |
| 35 Rw | 36 STC |
| 40 Rw | 41 STC |
| 45 Rw | 46 STC |
| 50 Rw | 51 STC |
| 55 Rw | 56 STC |
| 60 Rw | 61 STC |
| 65 Rw | 66 STC |
| 70 Rw | 71 STC |
Quick answers
Quick answers
- How many Rw is 1 STC?
- 1 STC is 0 Rw.
- How many Rw is 10 STC?
- 10 STC is 9 Rw.
- How many Rw is 50 STC?
- 50 STC is 49 Rw.
The units
About these units
STC (STC)
The North American sound transmission class, about one decibel above Rw.
Rw (Rw)
The international weighted sound reduction index, in decibels.
Keep going