How To Estimate VoIP Quality? Mean Opinion Score (MOS)

Some of you have asked us how we calculate a mean opinion score to estimate voice quality for over-the-top voice over internet protocol (VoIP) service. Well, here is the formula we use.

MOS

=IF(AND(ISNUMBER(R-value)),IF(AND(R-value>0,R-value<101),(1+0.035*R-value+0.000007*R-value*(R-value-60)*(100-R-value)),0),0)

R-value

=IF(Effective latency<160,(93.2-(Effective latency/40)-2.5*Avg. UDP packet loss),(93.2-(Effective latency-120)/10-2.5*Avg. UDP packet loss))

Effective latency

=Avg. latency + Avg. jitter*2+10