Standard uncertainty dB(A)	Component description
	Use of measuring instrumentation, ()
	Operating conditions, ()
	Microphone positions, ()
	Meteorological conditions, ()
	Angle error, ()
	Impedance of the surroundings, ()
	Influence of test room boundaries, ()
	Use of A-wt filter, ()

dB(A)	Calculated overall expanded uncertainty, U (at 95% confidance level using a coverage factor of 2)
dB(A)	Surface averaged sound pressure Level, Lp
(m2)	Enveloping surface area
dB(A)	Sound Power Level, Lw
dB(A)	Declared Noise Level (Lw + U)

Note: This calculator is only intended as a guide. A more accurate calculation of sound power may include further corrections. This software has not been subjected to NPL's Quality Assurance procedures. No warranty or guarantee applies to this software.