Calculator Inputs
Formula Used
1. Effective codec bitrate per session = nominal bitrate × channels × (1 + VBR uplift).
2. Packets per second = effective codec bitrate ÷ packet payload bits.
3. Protocol overhead bitrate = packets per second × overhead bytes × 8.
4. Container overhead bitrate = effective codec bitrate × container overhead %.
5. Network bitrate = codec bitrate + protocol overhead + container overhead + FEC overhead.
6. Safe required capacity = network bitrate × (1 + safety margin) × concurrent sessions.
7. Estimated transfer = network bitrate × duration ÷ 8000, returned as decimal megabytes.
How to Use This Calculator
- Pick a preset for a fast starting point, or choose Custom.
- Enter bitrate, payload size, interval, and overhead assumptions.
- Set session duration and concurrent stream count.
- Add VBR uplift, FEC, and safety margin for realistic planning.
- Enter available link capacity to measure utilization.
- Submit the form to view results, chart output, and export buttons above the form.
Example Data Table
| Codec | Nominal kbps | Channels | Sessions | Safe session kbps | Total Mbps | Total transfer GB |
|---|---|---|---|---|---|---|
| Opus Voice | 64.00 | 1 | 25 | 107.96 | 2.699 | 1.056 |
| AAC-LC Stereo | 192.00 | 2 | 12 | 512.71 | 6.152 | 3.708 |
| H.264 1080p | 2,500.00 | 1 | 6 | 3,619.68 | 21.718 | 4.249 |
| H.265 4K | 12,000.00 | 1 | 3 | 19,144.32 | 57.433 | 7.179 |
FAQs
1. What does this calculator estimate?
It estimates codec bitrate, packet overhead, total network load, storage transfer, and link utilization. It helps size WAN, LAN, or streaming capacity using realistic transport assumptions.
2. Why is network bitrate higher than codec bitrate?
Raw codec bitrate excludes protocol headers, container metadata, retransmission, and safety margin. Real transport always consumes more bandwidth than the media payload alone.
3. What is VBR peak uplift?
Variable bitrate streams can spike above their nominal average. The uplift field models those bursts so capacity planning is less optimistic.
4. How should I choose payload bytes per packet?
Use your transport profile, MTU target, or encoder packetization setting. Smaller payloads raise packets per second and therefore increase header overhead.
5. Does the calculator work for audio and video?
Yes. Audio presets use smaller payloads and shorter intervals, while video presets use larger payloads and higher nominal rates. Custom mode supports either case.
6. What does safety margin represent?
Safety margin adds planning headroom above modeled traffic. It protects against bursts, routing changes, mixed traffic, and future growth on the same link.
7. Are the transfer figures storage accurate?
They are practical estimates based on bitrate over time. Exact stored size can differ because containers, segmenting, encryption, and filesystem behavior vary by platform.
8. When should I use FEC or retransmission overhead?
Use it when your transport adds forward error correction, duplicate packets, or expected recovery traffic. It is especially useful on lossy or long-distance paths.