Frequency Weighting Calculator

Apply A, C, or Z weighting to octave band spectra and calculate weighted OASPL.

Input Spectrum
Enter SPL values at each frequency band center frequency
Freq (Hz)SPL (dB)A-Weight (dB)Weighted (dBA)
31.5-39.530.5
63-26.243.8
125-16.253.8
250-8.761.3
500-3.266.8
1k+0.070.0
2k+1.271.2
4k+1.071.0
8k-1.168.9
Spectrum Comparison
Visual comparison of unweighted vs A-weighted spectrum
Results
Unweighted OASPL
79.5 dB
Weighted OASPL
77.0 dBA
Active Weighting Curve
Reference

A-weighting: Approximates 40-phon equal-loudness contour. Used for occupational noise exposure and environmental regulations.

C-weighting: Nearly flat response. Used for peak measurements, low-frequency assessment, and C-A difference analysis.

Z-weighting: Flat/unweighted (0 dB at all frequencies). Used for engineering analysis and source characterization.

Weighting per IEC 61672-1:2013
Octave bands per IEC 61260-1:2014