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Mean Opinion Score (MOS) Calculator

Estimate VoIP call quality using the simplified ITU-T E-Model

End-to-end one-way delay including network, codec, and jitter buffer. ITU-T G.114 recommends <150ms for good quality.
ms
Packet delay variation. Contributes to effective delay through jitter buffer sizing. Should be <30ms for VoIP.
ms
Random packet loss percentage. VoIP quality degrades rapidly above 1%. Must be <3% for acceptable quality.
%
Voice codec determines baseline quality and equipment impairment factor (Ie). G.711 has highest quality but uses 64kbps. G.729 uses 8kbps with lower quality.

E-Model Results

Delay Impairment (Id)
Equipment Impairment (Ie-eff)
R-Factor
MOS Score
Quality Rating

Quality Thresholds

R ≥ 80 / MOS ≥ 4.0Good - Satisfied users
R 70-80 / MOS 3.6-4.0Acceptable - Some users dissatisfied
R 60-70 / MOS 3.1-3.6Poor - Many users dissatisfied
R < 60 / MOS < 3.1Unacceptable - Nearly all dissatisfied
References: ITU-T G.107 (E-model), ITU-T G.113 (equipment impairment factors), ITU-T G.114 (delay recommendations). R = 93.2 - Id - Ie_eff. MOS = 1 + 0.035R + R(R-60)(100-R)7e-6.