In short
BTnet leased line speeds run from 2Mbps to 10Gbps in steps based on Ethernet speeds. Every speed is symmetrical, so upload matches download, and uncontended, so the bandwidth is yours alone. Real throughput is typically 5-10% below the port speed because of network and IP overheads, as BT's terms explain.
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BTnet speeds at a glance
When people search for leased line speeds in the UK, they usually want three answers: how fast it can go, whether upload is as fast as download, and whether the speed holds up at busy times. For BTnet, BT's own material answers all three.
- 2Mbps to 10Gbps. BT's service schedule lists port speeds from 2Mbps up to 10Gbps, in increments based on Ethernet speeds. BT's plans show standard speeds up to 1Gbps, with up to 10Gbps available.
- Symmetrical. Uncontended, symmetrical bandwidth is a standard part of BTnet, so your upload speed is the same as your download speed. See symmetrical speeds.
- Uncontended. BT describes BTnet as 100% uncontended and dedicated: you do not share access or bandwidth with other users. See contended vs uncontended.
- No fair usage policy. BT's help pages say BTnet has no fair usage policy, so you can use as much data as your speed allows.
- Room to change. Bandwidth Flex lets you move your speed up or down within the capacity of your bearer.
- Low latency. BT's SLA includes a latency commitment on its UK core network. See leased line latency.
Port speed, bearer and throughput
Three different numbers get called the speed of a leased line. Knowing which is which avoids surprises when the line goes live.
| Term | What it means | Why it matters |
|---|---|---|
| Bearer | The physical access circuit to your site, for example a 100Mbps, 1Gbps or 10Gbps Ethernet fibre bearer | Sets the ceiling: you can flex the port speed up to the bearer's capacity, not beyond it |
| Port speed | The bandwidth you order and pay rental for, from 2Mbps to 10Gbps | This is your contracted speed, the same in both directions |
| Throughput | The data rate your applications and speed tests actually achieve | BT's terms say it is typically 5-10% below the port speed because of network and IP overheads |
The gap between port speed and throughput is normal for any Ethernet-based connection. Every packet carries addressing and control information as well as your data, and that overhead uses some of the line's capacity. BT's terms add that the exact figure depends on the application and is not fixed. Plan for it when you size the line, and use the right method when you check it: our leased line speed test guide explains how.
For the full detail on bearers, including the types BT offers and why some charges follow the bearer rather than the speed, see leased line bearers and port speeds.
Not sure which option fits? Ask us
Tell us what you need and we will recommend the right option for your organisation, with a quote.
Speed bands and the bearer behind them
BT's current BTnet service schedule sets out charges for five bearer types: 100Mbps, 1Gbps and 10Gbps Ethernet fibre bearers, and 1Gbps and 10Gbps data centre access bearers. Which one your site gets depends on the speed you want now, the speed you may want later and what the survey finds at your address.
| Port speed you want | Bearer that can carry it | Typical reasons to choose it | More detail |
|---|---|---|---|
| Up to 100Mbps | 100Mbps Ethernet fibre bearer, or a larger bearer for headroom | Smaller offices on cloud apps, calls and video meetings | 100Mbps leased line |
| Above 100Mbps up to 1Gbps | 1Gbps Ethernet fibre bearer (or a 1Gbps data centre access bearer) | Busier offices, heavy cloud use, large uploads, CCTV, hub sites | 1Gbps leased line |
| Above 1Gbps up to 10Gbps | 10Gbps Ethernet fibre bearer (or a 10Gbps data centre access bearer) | Large sites, campuses, data-heavy work, data centres | 10Gbps leased line |
BT's terms also refer to BTnet provided over Generic Ethernet Access on full fibre (FTTP). Whether that applies to your site, and at what speeds, is confirmed when we check availability and prepare your quote. See leased line vs FTTP for how the two technologies differ.
A common approach is to order the port speed you need today on a bearer big enough for the speed you expect to need later. BT's own published plan example is a 30Mbps or 50Mbps port speed delivered over a 1Gbps service, which shows how much room a larger bearer can leave for growth.
Why symmetrical, uncontended speed matters
Most broadband is asymmetric: download is fast, upload much slower. That suited a world where people mostly downloaded web pages. Today a business sends as much as it receives. Video meetings send your camera feed, cloud apps sync files back to the cloud, backups upload every night, and CCTV can stream to a cloud recorder all day.
On BTnet, the upload is the same as the download. A 100Mbps line gives you 100Mbps each way, and a 1Gbps line gives you 1Gbps each way. That is often the single biggest change people notice after moving from broadband.
Uncontended matters just as much. On a shared connection, your speed depends on what other users are doing at the same time, so performance tends to drop at busy periods. BT describes BTnet as fully uncontended and dedicated, so the bandwidth you order is reserved for your site. Combined with BT prioritising voice traffic on BTnet, that is why a leased line is the usual foundation for VoIP and cloud calling and Microsoft 365 and cloud apps.
Is BTnet the right fit for you?
We will check it against your systems and requirements and recommend the right option.
Speeds that can change with you
Your speed is not fixed for the life of the contract. BT's help pages say you can flex BTnet bandwidth up or down within the capacity of your bearer, with 72 hours' notice, and that rental changes pro rata for the period of the flex. BT's terms add some conditions: each flex is chargeable, it must run for at least five Business Days before another change, and a flex beyond what the BT equipment at your site can handle needs new equipment and starts a new Minimum Term.
That is why the bearer choice at the start matters. A bearer with headroom lets you add speed later with a flex rather than a new access line. Read Bandwidth Flex for how it works in practice, and the bandwidth sizing guide to work out where to start.
Choosing your speed with Forever Communications
You do not need to work this out alone. When you contact us, we can:
- Talk through how you use the connection: calls, video, cloud apps, backups, CCTV, guest Wi-Fi and remote access
- Suggest a starting port speed and a bearer with sensible headroom for the next few years
- Lay out the plan options at that speed: BTnet wires only, a managed Cisco router or BTnet Meraki
- Check availability at your address, including whether BTnet Express is an option
- Set out the costs for each option side by side, so you can see what more speed or a bigger bearer adds
We do not publish prices, because they depend on your site, bearer, speed and contract term. BT leased line cost explains what moves the price. Ask us for a quote: contact us with your postcode and what you use the connection for.
BTnet speeds in detail
Why buy BTnet from Forever Communications
Forever Communications is part of Forever Group and an Authorised Supplier for BT. We supply BTnet, BT's dedicated leased line internet service, to businesses, schools, charities and public sector organisations, and we help with each step from first enquiry to go-live.
- The right BTnet option for you: we help you choose a speed, bearer, router and resilience option that fits how your sites actually work, from BTnet plans to BTnet speeds
- A clear quote: BTnet is priced per site, so we check availability at your address and set out what is included; see leased line cost
- Installation managed with you: we explain the survey, any wayleave or construction steps and the installation process, and keep you updated on progress
- Connected services in one conversation: phones with BT Cloud Voice, Wi-Fi, firewalls and backup lines, so the whole set-up is planned together
- Help after go-live: we can help with faults, changes and upgrades, with the support arrangements confirmed in your quote
BTnet is a business service. Service levels, lead times and features are BT's and are confirmed at order.
Frequently asked questions
What speeds can a BTnet leased line get?
BT's terms list port speeds from 2Mbps to 10Gbps, in increments based on Ethernet speeds. BT's plans show standard speeds up to 1Gbps, with up to 10Gbps available. The speeds open to you depend on the bearer your site can have, which we confirm when we check availability at your address.
Is a leased line the same speed up and down?
Yes. Uncontended, symmetrical bandwidth is a standard part of BTnet, so your upload speed matches your download speed at whatever port speed you order. See symmetrical speeds.
Are leased line speeds guaranteed?
BT describes BTnet as 100% uncontended and dedicated, so you do not share bandwidth with other users. BT's terms also say real throughput is typically 5-10% below the port speed because of overheads, and that the exact figure varies by application and is not fixed.
Why is my speed test lower than my leased line speed?
Network and IP overheads take some capacity, and BT's terms put the typical reduction at 5-10%. Wi-Fi, firewalls, laptops and the test server can also limit results. See our leased line speed test guide.
Can I increase my leased line speed later?
Yes, within the capacity of your bearer, using BT's Bandwidth Flex. Going beyond the bearer means a bigger access line. See Bandwidth Flex.
What is the highest BTnet speed?
BT offers BTnet at up to 10Gbps, on a 10Gbps Ethernet fibre or data centre access bearer. See 10Gbps leased line.
Still have a question about BTnet?
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