Bandwidth Calculator
Size the bandwidth and monthly transfer a service needs.
What the Bandwidth Calculator does
Required bandwidth is the number of simultaneous users multiplied by what each consumes, plus an allowance for protocol overhead. Monthly transfer then follows from how many hours a day the service runs at that level — which is usually what a hosting bill is based on.
Formula
Bandwidth = Concurrent users × Per-user rate × (1 + Overhead)Monthly bytes = Bandwidth ÷ 8 × Hours × 3,600 × Days1 Mbps = 1,000,000 bits per second
Inputs explained
| Input | Unit | Required | Notes |
|---|---|---|---|
| Concurrent users or streams | number | Yes | Accepts more than 0. |
| Bandwidth per user | number | Yes | Accepts more than 0. |
| Per-user unit | one of 6 options | Yes | — |
| Protocol overhead | % | Yes | TCP/IP headers, retransmits and burst headroom. |
| Peak hours per day | number | Optional | Accepts 0 or more, up to 24. |
| Days per month | number | Optional | Accepts 1 or more, up to 31. |
How to use it
- Choose Per-user unit.
- Enter Concurrent users or streams, Bandwidth per user and Protocol overhead.
- Optionally add Peak hours per day and Days per month.
- Select Calculate.
Worked example
100 concurrent 1080p streams at 5 Mbps each, 20% overhead, 8 peak hours a day for 30 days.
- Users
- 100
- Per user
- 5 Mbps
- Overhead
- 20%
- Hours
- 8
- Days
- 30
500 Mbps raw becomes 600 Mbps with overhead — a 1 Gbps link. Monthly transfer is 64.8 TB.
Reading the result
- "As bytes per second" converts the network-speed convention (bits, decimal) into the storage convention (bytes) in one step — the two are easy to confuse and differ by a factor of 8.
- "Nearest standard link" turns a raw requirement into a purchasing decision — the practical question of which tier of hosting or ISP link actually covers it.
Assumptions and limitations
- "Concurrent users" is a single flat figure for the entire peak period — real traffic has its own burst variability within the peak hour, so provisioning exactly to this average leaves no margin for a moment where concurrency briefly exceeds it.
Common mistakes
- Comparing "bandwidth required" (bits per second) directly against a storage quota or file size (bytes) without converting — the two units look similar in magnitude but differ by a factor of 8, an easy mix-up when reading a hosting invoice.
Frequently asked questions
How much overhead should I allow?
15–25% for most services. TCP/IP headers are about 5%, and the rest covers retransmits, TLS handshakes and the burst headroom you need to avoid queuing.
Should I size for total users or concurrent users?
Concurrent, always. Peak concurrency is typically a small fraction of registered users, and that fraction is what your link has to carry.