Understanding Leased Line Speeds & Costs in the UK

What Makes Leased Line Speeds Different from Broadband

On a leased line, the speed you order is the speed you consistently receive — at 9am on Monday, at peak times on Thursday, and at any other point during the contract. This differs fundamentally from broadband, where the advertised speed is a maximum that may only be achieved during off-peak periods and which can fall considerably under real-world conditions.

Leased lines also provide symmetrical speeds: the upload rate equals the download rate. A 100Mbps leased line delivers 100Mbps upload and 100Mbps download. This matters for businesses running cloud backup, VoIP, video conferencing, or any workflow with significant data flowing out of the building as well as in.

Leased Line Speed Tiers and Their Costs (2025)

100Mbps

100Mbps is the most commonly ordered leased line speed in the UK, and the practical entry point for SME dedicated circuits. It suits teams of 10–40 users running cloud applications, VoIP, and video conferencing. Typical pricing in 2025:

• Well-connected city centre: from £199–£320/month
• Regional town: from £280–£450/month
• Rural location: from £450–£700+/month

500Mbps

500Mbps suits growing businesses and larger offices where 100Mbps is no longer providing adequate headroom, or where upload-intensive workloads require faster outbound speeds. Typical pricing:

• City centre: from £350–£500/month
• Regional town: from £420–£620/month
• Rural: from £650–£950+/month

1Gbps

1Gbps serves larger offices (50–200+ users), data-intensive operations, and multi-tenant buildings. The cost-per-Mbps at 1Gbps is significantly lower than at 100Mbps. Typical pricing:

• City centre: from £450–£700/month
• Regional town: from £550–£850/month
• Rural: from £800–£1,200+/month

10Gbps

10Gbps circuits are used by data centres, large enterprise campus sites, and organisations with extreme bandwidth requirements. They are not typically relevant for standard business premises but are available from most major providers in city-centre locations from around £2,000–£6,000/month.

The Cost-Per-Mbps Argument for Higher Speeds

One of the most consistent observations in leased line pricing is that cost-per-Mbps falls sharply as you move up the speed tiers. Using a city-centre example:

• 100Mbps at £250/month = £2.50/Mbps
• 500Mbps at £420/month = £0.84/Mbps
• 1Gbps at £580/month = £0.58/Mbps

This means that if you anticipate needing more than 200–300Mbps within your contract period, ordering 500Mbps or 1Gbps from the outset is usually more economical than ordering 100Mbps and upgrading mid-contract. Mid-contract speed upgrades often involve a contract extension and, in some cases, re-installation charges.

How to Choose the Right Speed

The right speed depends on three factors:

• Current user count: Allow 2–4Mbps per concurrent user for mixed cloud and communication use. 30 users need 60–120Mbps minimum; 75 users need 150–300Mbps minimum.
• Upload requirements: Heavy cloud backup, video production, or remote server access? Double your upload estimate and order accordingly.
• Growth expectations: If you will need more bandwidth within 36 months, order for your anticipated peak, not your current position.

SLA and the Speed Relationship

The SLA on a leased line applies regardless of speed — a 100Mbps circuit and a 1Gbps circuit can both carry the same 4-hour fix guarantee. However, the financial impact of a fault is proportionally higher at higher speeds because the business operational dependency is typically greater. At 1Gbps, an enhanced SLA (4-hour MTTR, diverse routing option) is worth factoring into the budget from the outset.

AMVIA helps UK businesses match the right speed and SLA tier to their specific usage requirements, running availability checks across multiple networks to identify the best options at each speed tier for a given postcode.