Rw to STC
Type a value in Rw to get it in STC instantly.
That's 3.2× as quiet as a blockwork wall, while a party wall is 2× better. A 75 dB television next door would come through at about 25 dB.
Convert the other way: STC to Rw
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 Rw to STC
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 Rw = 51 STC.
Every unit
Your rating in every unit
Tables
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 |
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 |
Quick answers
Quick answers
- How many STC is 1 Rw?
- 1 Rw is 2 STC.
- How many STC is 10 Rw?
- 10 Rw is 11 STC.
- How many STC is 50 Rw?
- 50 Rw is 51 STC.
The units
About these units
Rw (Rw)
The international weighted sound reduction index, in decibels.
STC (STC)
The North American sound transmission class, about one decibel above Rw.
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