Bandwidth Throughput Requirement Calculator
Size the internet or network link you need for N users — from an average per user or from an activity mix (browsing, video calls, streaming, VoIP) — with download and upload, headroom, the next standard plan size, growth and monthly data.
How it works
Average mode: concurrent demand = users × active% × per-user Mbps · Activity mode: demand = Σ (sessions × Mbps per session), separately for download and upload · Recommended = demand × (1 + headroom%) · Future = recommended × (1 + growth%)^years · Monthly data (GB) = (down + up Mbps) × busy hours × 3,600 × days ÷ 8 ÷ 1,000
You almost never need to size a link for every user at full speed at once. In “Average per user” mode the calculator multiplies the user count by the share realistically active at peak, then by the bandwidth each active session uses; upload is estimated as a share of that. In “Activity mix” mode you say how many people are browsing, on video calls, on voice calls, streaming or gaming at the same moment, and each activity adds its own download and upload rate — taken from Zoom’s and Netflix’s published requirements — so upload-heavy work like video meetings shows up properly. A headroom margin then absorbs bursts, protocol overhead and growth so the link is not saturated at peak. The results round the answer up to the next common plan or port size (100 Mbps, 500 Mbps, 1 Gbps, 10 Gbps…) and show how full that link would be at peak, the share each user gets when everyone is online, an optional growth projection and a rough monthly data volume for plans with a cap. Under-provisioning shows up as frozen calls and slow pages during busy periods; a modest margin is far cheaper than a congested link.
Worked example
100 users, 70% active at peak, each using 5 Mbps: 100 × 0.70 × 5 = 350 Mbps of concurrent demand. Adding 20% headroom gives 350 × 1.20 = 420 Mbps — so a 500 Mbps plan covers it, running at 70% at peak. With upload at 25% of download, the link must also carry 105 Mbps up. By activity instead: 40 people browsing (40 × 3 = 120 Mbps), 10 in video meetings (18 Mbps down, 26 up), 5 on voice calls (0.5 each way) and 5 streaming HD (25 Mbps) need 163.5 Mbps down and 47 Mbps up, or 196.2 / 56.4 Mbps with 20% headroom — a 200 Mbps plan whose upload is at least 60 Mbps.
Sources: Zoom: system requirements — bandwidth · Netflix: internet connection speed recommendations · FCC: Household broadband guide
Frequently asked questions
What concurrency should I assume?
It depends on the workload. Office web browsing might see 30–50% truly active at once, whereas a call centre or a classroom streaming video can approach 100%. Use peak-hour behaviour, not the daily average — or switch to “Activity mix” and count what people actually do in the busiest hour.
How much bandwidth does each activity need?
Rough per-person figures: email and browsing 1–3 Mbps, voice calls about 0.1 Mbps each way, group HD video meetings about 1.8 Mbps down and 2.6 Mbps up (Zoom), Full HD streaming 5 Mbps and 4K streaming 15 Mbps (Netflix). These are the defaults in Activity mix mode.
Do I need to worry about upload speed?
Yes, for video meetings, cloud backup, CCTV and file sharing. A video call sends more than it receives, so an office full of meetings can run out of upload long before download. Many cable and DSL plans upload a tenth of what they download; fiber and dedicated links are usually symmetric.
Is this the same as guaranteed speed per user?
No. This sizes the shared link for aggregate peak demand. If you need each user guaranteed a minimum, size for users × per-user with little or no concurrency discount — set “Active at the same time” to 100%.
Why add headroom?
Real traffic is bursty and protocols carry overhead, so a link running at 100% of average demand feels slow. A 20–30% margin keeps latency low during spikes; the “Peak load on that link” result shows how full the next standard plan would be.
How do I plan for growth?
Enter an annual growth rate under More options. Business traffic commonly grows 20–30% a year as video and cloud apps spread; the growth table shows the recommended link and standard size for each year so you can pick a plan that lasts the contract term.
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This calculator is for educational purposes. Double-check important results before acting on them.