Enter users and expected activity.
Speed & transfer
Bandwidth Calculator
Work out how much internet speed a home or small office really needs from the number of people, what they do and how often they overlap.
Short answer: multiply the number of active users by what each one needs, adjust for how many are active at the same moment, then add some headroom. The result is the plan size you should shop for.
Why not just add everything up?
Because nobody uses everything at once. If four people each might need 10 Mbps, you probably do not need 40 Mbps every minute of the day. The “peak overlap” box lets you say what share of people are really busy together. Home evenings are often 60 to 100%, office hours may be lower.
The formula
Required Mbps = users × Mbps each × peak overlap × (1 + margin).
Example
Four people at 10 Mbps each, everyone online together, with 25% margin: 4 × 10 × 1.25 = 50 Mbps. If only half of them are busy at once, it drops to 25 Mbps. The tool then rounds up to the nearest common plan size so you know what to pick.
Choosing the “Mbps each” number
- Browsing and email: 2 to 5 Mbps
- HD streaming or a video call: 5 Mbps
- 4K streaming: 25 Mbps
- Large downloads or backups: 20 Mbps and up
Not sure what everyone does? The Internet Speed Requirement Calculator lets you tick activities instead.
FAQ
Frequently asked questions about the Bandwidth Calculator
How much bandwidth do I need for a family of four?
For typical use, 100 Mbps is comfortable. Streaming in 4K on two screens while others work or game is easier with 200 Mbps.
What safety margin should I add?
20 to 30% is a good starting point. It absorbs Wi-Fi losses and the odd spike without you paying for a much bigger plan.
Is bandwidth the same as speed?
Close enough in everyday use. Bandwidth is the maximum amount of data per second your line can carry, while speed is usually what you measure at a given moment.
Does upload bandwidth count?
Yes. Add your upload needs separately for calls, backups and streaming out. Many plans have much less upload than download.
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Use this toolResults are estimates for planning. Last reviewed 2 October 2026.