Calculator Inputs
Use the fields below to model fair share, guaranteed share, and capacity planning.
Bandwidth Projection Graph
This chart shows how bandwidth per weighted user changes as simultaneous users increase.
Example Data Table
| Scenario | Total Bandwidth | Users | Peak Concurrency | Effective Capacity | Weighted Mbps per User | Required Raw Bandwidth |
|---|---|---|---|---|---|---|
| Small Office | 150 Mbps | 35 | 35% | 109.09 Mbps | 7.42 Mbps | 101.06 Mbps |
| Campus Wi-Fi | 800 Mbps | 300 | 30% | 518.14 Mbps | 5.76 Mbps | 694.79 Mbps |
| Streaming Lounge | 1,000 Mbps | 180 | 45% | 638.82 Mbps | 4.38 Mbps | 1,825.87 Mbps |
| Hybrid Team Hub | 600 Mbps | 90 | 40% | 407.38 Mbps | 7.80 Mbps | 461.29 Mbps |
Formula Used
Usable capacity after reserve = Total bandwidth × (1 − reserved capacity %)
Effective capacity = Usable capacity × (1 − protocol overhead %) × safe utilization %
Estimated active users = Total users × peak concurrency %
Weighted active users = Estimated active users × traffic profile weight
Bandwidth per active user = Effective capacity ÷ estimated active users
Weighted user share = Effective capacity ÷ weighted active users
Guaranteed shared minimum = (Effective capacity ÷ total users) ÷ contention ratio
Required raw bandwidth = (Planning target × weighted active users) ÷ adjustment factors
This model helps estimate both fair share performance and the raw circuit size needed to meet a target level during peak load.
How to Use This Calculator
- Enter total available bandwidth for the connection or network segment.
- Add the number of users who can access the service.
- Choose a realistic peak concurrency percentage for busy periods.
- Set reserved capacity, protocol overhead, and safe utilization values.
- Enter average devices per active user and the percentage active together.
- Choose a traffic profile to weight heavy or light usage patterns.
- Set your target Mbps per user and contention ratio.
- Submit the form to review calculated capacity, fair share, graph, and exports.
Frequently Asked Questions
1. What does bandwidth per user mean?
It estimates how much usable bandwidth each active person can receive during shared network use. It is a planning metric, not a fixed guarantee, because real demand changes by application, overhead, and concurrency.
2. Why is peak concurrency important?
Peak concurrency tells the calculator how many users are active at the same time. Higher concurrency lowers the available share per user and usually raises the raw bandwidth needed to maintain service quality.
3. What is the difference between active user share and weighted user share?
Active user share treats all active users equally. Weighted user share adjusts the calculation for heavier traffic profiles, such as video meetings or streaming, so capacity planning reflects real demand better.
4. Why include reserved capacity and protocol overhead?
Reserved capacity keeps room for resilience, control traffic, or priority workloads. Protocol overhead reflects packet headers, retransmissions, and signaling that consume bandwidth without directly reaching user applications.
5. How should I choose a contention ratio?
Use a lower ratio when service consistency matters, such as business links or voice traffic. Higher ratios may reduce cost, but they increase the chance of slower performance during busy periods.
6. Can this calculator help size internet plans?
Yes. The required raw bandwidth result shows the estimated line size needed to meet your chosen per-user target after reserve, overhead, utilization, and concurrency assumptions are applied.
7. Does more bandwidth always solve congestion?
Not always. Congestion can also come from poor Wi-Fi coverage, shaping policies, overloaded routers, or application spikes. Bandwidth helps, but the network path and hardware still matter.
8. Which traffic profile should I select?
Pick the closest match to your busiest normal workload. Mixed office fits general teams, video meetings fits collaboration-heavy environments, and streaming profiles better represent media-dense shared networks.