Decibels sound power to pressure level at 1 m
Type a value in dB SWL to get it in dB at 1 m instantly.
79dB at 1 m
That's 3.2× as loud as a vacuum cleaner, while a pneumatic drill is 100× louder. That is about 0.001 acoustic watts.
Convert the other way: dB at 1 m to dB SWL
What it means
How much sound is that?
The one-metre figure assumes a source radiating equally in all directions in free space. Near a wall or a floor the level is higher.
The math
How to convert dB SWL to dB at 1 m
Sound power level is referred to one picowatt: dB SWL = 10 × log₁₀(W ÷ 10⁻¹²). The pressure level at one metre in free space is 11 dB lower.
Example: 90 dB SWL = 79 dB at 1 m.
Every unit
Your sound power in every unit
Tables
dB SWL to dB at 1 m conversion table
| dB SWL | dB at 1 m |
|---|---|
| 20 dB SWL | 9 dB at 1 m |
| 40 dB SWL | 29 dB at 1 m |
| 60 dB SWL | 49 dB at 1 m |
| 70 dB SWL | 59 dB at 1 m |
| 80 dB SWL | 69 dB at 1 m |
| 90 dB SWL | 79 dB at 1 m |
| 100 dB SWL | 89 dB at 1 m |
| 110 dB SWL | 99 dB at 1 m |
| 120 dB SWL | 109 dB at 1 m |
| 140 dB SWL | 129 dB at 1 m |
dB at 1 m to dB SWL conversion table
| dB at 1 m | dB SWL |
|---|---|
| 20 dB at 1 m | 31 dB SWL |
| 40 dB at 1 m | 51 dB SWL |
| 60 dB at 1 m | 71 dB SWL |
| 70 dB at 1 m | 81 dB SWL |
| 80 dB at 1 m | 91 dB SWL |
| 90 dB at 1 m | 101 dB SWL |
| 100 dB at 1 m | 111 dB SWL |
| 110 dB at 1 m | 121 dB SWL |
| 120 dB at 1 m | 131 dB SWL |
| 140 dB at 1 m | 151 dB SWL |
Quick answers
Quick answers
- How many dB at 1 m is 1 dB SWL?
- 1 dB SWL is -10 dB at 1 m.
- How many dB at 1 m is 10 dB SWL?
- 10 dB SWL is -1 dB at 1 m.
- How many dB at 1 m is 90 dB SWL?
- 90 dB SWL is 79 dB at 1 m.
The units
About these units
Decibels sound power (dB SWL)
The standard rating, referred to one picowatt.
Pressure level at 1 m (dB at 1 m)
What a meter would read one metre away in free space.
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