1 Gbps vs 100 Mbps leased line — which do you actually need?
Independent, jargon-free guide to right-sizing a UK leased line. Most SMEs pay for far more bandwidth than they use. Here's how to work out the real number.
The 30-second answer
If your business has fewer than 50 people and doesn't host anything on-site, 100–200 Mbps symmetric is enough. You don't need 1 Gbps unless you have 100+ concurrent users, run on-site servers, or do heavy video/CAD/data work. The 1 Gbps bearer with a 200 Mbps port is usually the smart compromise.
Bandwidth needs by team size
| Team size | Typical use | Right-sized bandwidth | Typical cost |
|---|---|---|---|
| 5–15 users | Cloud tools, some video calls | 100 Mbps | £200–£300/mo |
| 15–35 users | Cloud + hosted VoIP + regular video | 200 Mbps | £300–£500/mo |
| 35–75 users | Heavy cloud + video + occasional large transfers | 500 Mbps | £500–£800/mo |
| 75–150 users | All of the above + on-site hosting | 1 Gbps | £700–£1,200/mo |
| 150+ users, on-site SaaS/servers | Bandwidth-critical workload | 1 Gbps+ or dual circuit | £1,000+/mo |
100 Mbps vs 1 Gbps — head to head
| 100 Mbps | 1 Gbps | |
|---|---|---|
| Typical monthly cost | £200–£350 | £700–£1,200 |
| Concurrent HD video calls | ~15–20 | 150+ |
| Full cloud backup of 500 GB | ~11 hours | ~1.2 hours |
| Comfortable user count | 10–25 | 100+ |
| Symmetric upload | Yes | Yes |
| SLA | Same 99.9%+ / 4-hr fix | Same 99.9%+ / 4-hr fix |
| Future-proof for growth | Limited | Yes |
The smart middle ground: 1 Gbps bearer, 200 Mbps port
Every leased line has two speeds: the bearer (physical capacity of the fibre delivered to your building) and the port (the speed you actually pay for and use). Ordering a 1 Gbps bearer with a 200 Mbps port costs about £30–£50/mo more than a straight 200 Mbps line — but upgrading the port to 500 Mbps or 1 Gbps later is a same-day software change with no new install, no new contract, and no downtime.
Ordering a 200 Mbps bearer and needing more later means a full rebuild — new install, new contract, new lead time (45–90 days). The bearer upgrade insurance is almost always worth it.
Frequently asked questions
Do I need a 1 Gbps leased line or is 100 Mbps enough?
For most UK SMEs under 50 users, 100–200 Mbps is enough. You only genuinely need 1 Gbps if you have 100+ concurrent users, host your own servers/SaaS on-site, do heavy video production, or run frequent large file transfers (CAD, video, medical imaging). Paying for 1 Gbps when you use 80 Mbps is money wasted.
What's the price difference between 100 Mbps and 1 Gbps?
In the UK in 2026: 100 Mbps typically runs £200–£350/mo, 1 Gbps runs £700–£1,200/mo. That's roughly 3–4x the cost for 10x the bandwidth. The smart middle ground is a 1 Gbps bearer with a 200 Mbps port — you pay ~£400/mo and can upgrade to full 1 Gbps in an afternoon when you actually need it.
How do I work out what bandwidth I actually need?
Rough formula: (concurrent users × 5 Mbps for typical cloud/video use) + (headroom of 30%). A 30-person office running Teams, Google Workspace and hosted VoIP needs about 200 Mbps. A 100-person office needs 500–700 Mbps. Add another 200–300 Mbps if you host anything on-site (servers, SaaS, e-commerce).
Is symmetric bandwidth (equal upload and download) worth paying for?
Yes for any business using cloud backup, video conferencing, VoIP or hosting on-site services. Standard broadband gives you 20 Mbps upload against 900 Mbps download; a leased line at 200/200 Mbps feels dramatically faster in daily use because upload is usually the bottleneck.
Can I start on 100 Mbps and upgrade later?
Yes, and it's usually the smart move. Order the circuit with a 1 Gbps bearer (the physical capacity) but only pay for a 100 or 200 Mbps port initially. Upgrading the port speed is a same-day software change — no re-install, no new contract. Ordering the wrong bearer means a full rebuild.
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