SIP VoIP Trunk Bandwidth, Codec Packetization & Overhead Calculator
Calculate real-world telecom bandwidth requirements for SIP trunks, PBX phone systems, and call centers. Model G.711 (u-law/a-law), G.729, G.722 HD, Opus, and AMR-WB codecs with IP/UDP/RTP protocol overhead, ptime packetization, and cRTP compression.Documentation & FAQs ↓
VoIP SIP Trunk Codec Bandwidth & Packet Overhead Calculator
L2 Ethernet 802.1Q VLAN, IPv4/IPv6, UDP, RTP packetization overhead, PPS flow & trunk dimensioning.
Voice Codec & Packetization Config
Uncompressed pulse-code modulation standard. High fidelity, heavy bandwidth.
Adds +20 bytes per packet (40B vs 20B)
Layered Packet Header Anatomy (238 Total Bytes / Packet)
Guarantees jitter-free headroom for 25 concurrent G.711u (PCMU / North America) sessions without packet dropping.
SIP Trunk Capacity Dimensioning Matrix
| Concurrent Calls | Raw Bandwidth | +20% Headroom | Packet Flow (PPS) |
|---|---|---|---|
| 5 Channels | 0.48 Mbps | 0.58 Mbps | 250 PPS |
| 10 Channels | 0.95 Mbps | 1.14 Mbps | 500 PPS |
| 25 Channels | 2.38 Mbps | 2.86 Mbps | 1,250 PPS |
| 50 Channels | 4.76 Mbps | 5.71 Mbps | 2,500 PPS |
| 100 Channels | 9.52 Mbps | 11.42 Mbps | 5,000 PPS |
| 250 Channels | 23.80 Mbps | 28.56 Mbps | 12,500 PPS |
| 500 Channels | 47.60 Mbps | 57.12 Mbps | 25,000 PPS |
Step-by-Step Instructions
4 Steps to CompletionSelect your primary VoIP codec (e.g., G.711u, G.729a, G.722 HD, or Opus Voice).
Choose packetization interval (default 20ms) and network encapsulation (Ethernet IPv4, IPv6, or VLAN tagged).
Input the maximum number of concurrent telephone calls your business handles during peak hours.
Toggle Voice Activity Detection (VAD) or cRTP header compression to view required bandwidth in kbps and Mbps with recommended safety margins.
Practical Use Cases & Real-World Scenarios
Comprehensive Voice Codec Library
Models bitrates and MOS quality scores across G.711 (64 kbps), G.729 (8 kbps), G.722 HD voice (64 kbps), Opus Adaptive (6–510 kbps), and iLBC.
Layer 2 & Layer 3 Packet Overhead Modeling
Factors in exact packet headers: Ethernet (14B + 4B FCS), IPv4 (20B) or IPv6 (40B), UDP (8B), and RTP (12B) headers for authentic wire speeds.
Packetization Interval (ptime) Tuning
Adjust packetization intervals (10ms, 20ms, 30ms, 40ms) to analyze how smaller payloads trade audio latency for higher network header overhead.
VAD / Silence Suppression & Trunk Sizing
Simulates Voice Activity Detection (VAD) with ~35% bandwidth savings across concurrent trunk call volumes to properly size ISP committed information rates (CIR).
Frequently Asked Questions
Why does a 64 kbps G.711 voice call actually consume 87.2 kbps on the wire?↓
What is ptime (packetization interval) and how does it affect bandwidth?↓
How much bandwidth does Voice Activity Detection (VAD) save?↓
What is the Mean Opinion Score (MOS) of popular codecs?↓
How much internet bandwidth headroom should an enterprise reserve for VoIP?↓
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Dive deeper into the foundational technical concepts behind this tool on our editorial blog. Includes comprehensive hardware benchmarks, case studies, and best practices.
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