Enter the total sound level in decibels and the total time of exposure into the calculator to determine the total weight average (TWA) noise exposure.

- SNR (Signal-to-Noise Ratio) Calculator
- Sound Pressure Level Calculator
- Decibel Calculator
- Pure Tone Average Calculator
- Sound Reduction Index Calculator

## TWA Formula

The following formula is used to calculate the total weight average noise exposure.

TWA = 16.61 * log_{10}* (D/100) + 90

D = 100 * (C / ( 2 ^^{ ( L-90)/5} ) )

- Where TWA is the total weight average noise exposure rating
- C is the total time of exposure
- L is the total A-weight sound level (decibels)

* Note this calculation assumes the sound level is constant for the entire duration of the day.

## TWA Definition

**What is TWA? **

TWA stands for total weighted average. This term is most often used in OSHA regulations to denote a total weighted average of sound exposure.

This value is used to determine the risk associated with a loud work environment.

## Example Problem

How to calculate TWA?

**First, determine the total time of exposure.**For this example, we will use a standard 8 hour workday as the time exposure.

**Next, determine the A-weighted sound level.**For this problem, the A-weighted sound level is found to be 82 decibels.

**Finally, calculate the TWA.**Using the formula above, the TWA is calculated to be:

TWA = 16.61 * log(10) * (D/100) + 90

D = 100 * (8 / ( 2 ^^{ ( 82-90)/5}) )

TWA = 113