100Mbps leased line: who it suits

What a 100Mbps leased line gives you

A 100Mbps BTnet line is not the same as 100Mbps broadband. The difference is in three places:

• 100Mbps each way. BTnet bandwidth is symmetrical, so you get 100Mbps upload as well as 100Mbps download. On most broadband, upload is a fraction of download.
• Reserved for you. BT describes BTnet as 100% uncontended and dedicated. Your 100Mbps is not shared with neighbouring businesses, so it does not shrink at busy times.
• Backed by BT's SLA. BTnet comes with BT's availability, on-time delivery and latency service levels, with service credits set out in BT's terms. See the BTnet SLA.
• Static IP addresses. Static assigned IPv4 addresses are standard, which helps with VPNs, remote access and allow-listing. See static IP addresses.

As with any Ethernet connection, the data rate your applications see is a little below the port speed. BT's terms put the reduction at typically 5-10%, varying by application. So on a 100Mbps port, expect speed tests in the low-to-mid 90s rather than exactly 100Mbps, measured over a wired connection.

What 100Mbps of symmetrical bandwidth handles

There is no single answer to how many people a 100Mbps leased line supports, because it depends on what they do, at the same time. A team that works mostly in cloud apps and on calls uses bandwidth very differently from a design studio uploading large files all day.

What 100Mbps of dedicated, symmetrical bandwidth does well:

• Calls and video meetings, because each call needs steady bandwidth in both directions, and BT prioritises voice traffic on BTnet
• Cloud apps and Microsoft 365, where documents, email and shared files move constantly in both directions
• Overnight and daytime backups, which upload at the full line rate instead of the slow upload of broadband
• Remote access, with staff connecting back into office systems over VPN using the site's upload
• A modest number of cloud CCTV cameras, sized from your camera supplier's figures

Where 100Mbps can start to feel tight is when several heavy, simultaneous uses stack up: large file transfers during video meetings, many cameras streaming continuously, or a busy guest Wi-Fi network. Our bandwidth sizing guide shows how to add up your own peak use rather than relying on rules of thumb.

The bearer decision: 100Mbps or 1Gbps underneath

BT can deliver a 100Mbps port speed on two different kinds of access line, and the choice affects how you grow.

BT's terms set cancellation, termination and Service Introduction Charges by the bearer rather than the port speed. In BT's current schedule, the amounts listed for the 100Mbps and 1Gbps Ethernet fibre bearers are the same. Your rental and the exact charges are set in your quote and order, so we show both options side by side.

If you think you may need more than 100Mbps within the contract term, a larger bearer is usually worth pricing. See leased line bearers and port speeds and Bandwidth Flex.

Speeds below 100Mbps

BTnet port speeds start at 2Mbps, and BT's own published plan example is a 30Mbps or 50Mbps port speed delivered over a 1Gbps service. So 100Mbps is not the entry point.

A lower port speed can make sense for a small site that values a dedicated, symmetrical connection and BT's SLA more than raw speed, for example a branch office running cloud apps and a few calls. Because the bearer sets the ceiling rather than the port speed, a lower speed on a larger bearer keeps the option to flex up as the site grows.

Signs 100Mbps is right, and signs it is not

100Mbps is often a good fit when:

• Broadband upload is the main bottleneck today, not download
• Calls and video meetings break up when someone uploads a large file or a backup runs
• Your team is office-based and works mainly in cloud apps, email and video
• You want BT's SLA and static IPs without paying for capacity you will not use

Look at 1Gbps or a larger bearer when:

• You move large files daily, such as design, video, imaging or engineering data
• You run many cloud CCTV cameras or other continuous uploads
• The site is a hub that other sites or remote staff connect into
• You expect headcount or cloud use to grow noticeably during the contract

See 1Gbps leased line for the next step up.

Getting a 100Mbps BTnet quote

Every BTnet quote depends on the site, so we do not publish prices. The main factors are the bearer, the port speed, the contract term, the plan (wires only, managed Cisco router or Meraki), options such as BTnet Security and BTnet Wi-Fi, any resilience and any extra construction needed to reach you. BT leased line cost explains each one.

Installation is subject to survey. BT's help pages say a new BTnet service can take up to 70 working days depending on the survey, while BTnet Express services on easy-to-install cabling typically take 35-40 working days where available. BT gives you a Customer Committed Date after survey.

Ask us for a quote. Contact us with your postcode and how you use the connection, and we will price 100Mbps on the bearer options available at your address.