Decibel Calculator:
This form allows you to add two or more sound source decibel levels together to give a total sound db level.

To use this form, simply fill-in the source level text boxes below,
then click "calculate".
The answer will appear in the output level field.

Source level 1 (db) 
Source level 2 (db) 
Source level 3 (db) 
Source level 4 (db) 
Source level 5 (db) 
Source level 6 (db) 
Source level 7 (db) 
Source level 8 (db) 
Source level 9 (db) 
Total level (db) 

The decibel calculator can be used to combine the sound levels of two
sound sources when the level of each source is given in decibels (db).
The calculator can be used to combine any "like quantity" that
is expressed in decibels. for example, you can combine two a-weighted
sound levels, or two octave band sound levels, or two 1/3-octave band
sound levels, or two un-weighted sound levels. However, you cannot combine
unlike quantities (e.g. one a-weighted sound level and one un-weighted
sound level, or one sound power level and one sound pressure level). The
only additional restriction is that the two sounds must be incoherent.
Most noise sources are random and incoherent, but some are not. The most
common example of a coherent sound is a sound that contains a strong pure