Bandwidth Calculator
Bandwidth requirements come from what everyone is doing at once, not from the number of devices connected. This calculator adds up simultaneous demand.
Formula
Transfer time = file size in megabits ÷ connection speed in Mbps
- Megabytes × 8 = megabits
- A gigabyte here is 1,024 MB
A 2 GB file on 100 Mbps: 2,048 MB × 8 ÷ 100 = 164 seconds
What Each Activity Needs
- Web browsing and email: 1–5 Mbps
- HD video streaming: 5–8 Mbps per stream
- 4K streaming: 15–25 Mbps per stream
- Video calls: 2–4 Mbps
- Online gaming: 3–6 Mbps, though latency matters more than throughput
A household with two 4K streams, a video call and general browsing needs roughly 60 Mbps at peak.
Upload Matters More Than It Used To
Most UK broadband is asymmetric: a 100 Mbps package might offer only 10–20 Mbps upstream. That was fine when households mostly consumed content.
Video calls, cloud backup and working from home all push data outward, and upload is usually the first thing to saturate. If calls stutter while downloads stay fine, upload is the constraint. Full-fibre (FTTP) services often offer symmetric speeds, which is their main practical advantage.
Speed Is Often Not the Problem
Beyond about 100 Mbps, most households notice little from further increases. The bottleneck is usually elsewhere:
- Wi-Fi rather than the line, particularly on older standards or at distance
- Latency, which determines responsiveness and is unrelated to bandwidth
- Contention at peak times, where a shared connection slows in the evening
UK advertising rules require providers to quote speeds achievable by at least 50% of customers at peak, so the headline figure is a realistic median rather than a best case.
Quick Reference
| Activity | Bandwidth each | 4 at once |
|---|---|---|
| Web browsing | 1–5 Mbps | 20 Mbps |
| HD video call | 3–4 Mbps | 16 Mbps |
| 1080p streaming | 5 Mbps | 20 Mbps |
| 4K streaming | 25 Mbps | 100 Mbps |
| Online gaming | 3–6 Mbps | 24 Mbps |
Frequently Asked Questions
- How much broadband speed do I need?
- Add up simultaneous activity. A household with two 4K streams and a video call needs roughly 60 Mbps; most homes are comfortable between 50 and 100.
- Why do video calls stutter when downloads are fine?
- Calls depend on upload, which is far lower than download on most UK packages. It saturates first.
- Is faster broadband always better?
- Beyond about 100 Mbps most households notice little difference. Wi-Fi quality and latency usually matter more than headline speed.
- What is the difference between bandwidth and latency?
- Bandwidth is how much data can flow per second; latency is how long each packet takes. Gaming and calls depend far more on latency.