1Gbps vs 10Gbps Leased Line: Which Should You Order?

This is the comparison growing businesses ask for when the 100Mbps circuit they bought three years ago is full and they want to size the next one properly. The short version: 1Gbps is the right order for nearly all of them, but the way it is ordered matters as much as the number, and that is where the 10Gbps question comes in. The 1Gbps cost guide and the 10Gbps cost guide hold the regional pricing; this page is about the decision between them.

How much bandwidth does an office actually use?

Less than its buyers assume. A 200-person office on Microsoft 365, hosted telephony and daily video meetings typically peaks at a few hundred megabits, with the average far lower. What makes a gigabit circuit feel essential is not throughput but the things a leased line gives at any speed: symmetric upload, no contention and a fix-time SLA. A 1Gbps circuit gives that office two or three times its peak as headroom, which is exactly what you want. A 10Gbps circuit gives it twenty-five times its peak, which is capacity you are paying to leave idle. Gigabit-capable networks passed 87% of UK premises by Q3 2025 (Ofcom Connected Nations 2025), so a 1Gbps bearer is now the default build at most addresses and 10Gbps is usually a bearer upgrade rather than a new route.

Who genuinely needs 10Gbps

Four kinds of buyer. Campuses and head offices that aggregate several hundred or several thousand users, their telephony and their guest networks onto one circuit. Data-heavy operations: media production, engineering firms moving CAD and simulation data, research groups, and anyone replicating storage to the cloud or a second site every night, where the job either finishes inside the window or it does not. Buildings that are the product: multi-tenant offices, co-working operators and managed-service providers selling bandwidth to the companies inside, where ten gigabits is divided many ways. And multi-site businesses that bring branch traffic back to one hub over private links. If you recognise your business in that list, 10Gbps is the right order and the multi-gigabit cost guide shows what the band is quoted at by region. If you do not, it probably is not.

The bearer decision matters more than the speed decision

Every leased line has two numbers: the bearer, which is the physical capacity of the fibre and optics installed, and the committed rate, which is the bandwidth you pay for. Historically a 1Gbps service came on a 1Gbps bearer. In well-served commercial postcodes carriers now install 10Gbps bearers as standard and price the committed rate, so a 10Gbps bearer carrying 1Gbps or 2Gbps lands close to a plain gigabit price. The consequence is that the expensive mistake is not choosing 1Gbps over 10Gbps; it is accepting a 1Gbps bearer at a site that will outgrow it, because the upgrade is then a new circuit, a new survey and another 30 to 90 working-day wait. Ask for the bearer in writing and have the upgrade price per step put in the contract.

What 10Gbps costs beyond the circuit

The hand-off above 1Gbps is a 10GBASE optical interface, and the firewall, router and core switch have to terminate it at line rate. A 10Gbps circuit behind a 1Gbps firewall port is a 1Gbps connection with a larger invoice. Budget the equipment refresh alongside the circuit, or order the 10Gbps bearer with a 1Gbps committed rate on a 1GBASE hand-off and plan the refresh for the upgrade. Multi-gigabit orders are also likelier to need new optics at the exchange or new fibre into the building, so the lead time can run past the usual 30 to 90 working days and an excess construction charge is more likely where no high-capacity fibre reaches the site yet.

Pricing both at the postcode

Entry pricing for 1Gbps from £129/month and 10Gbps from £349/month applies in postcodes where several carriers already have fibre in the building. Elsewhere both tiers rise toward £1,200 or more and the gap between them changes shape, which is why the comparison is only meaningful as a multi-carrier quote for your address. The UK leased line cost breakdown covers every tier, and the UK leased line providers comparison sets out which carriers are strong at multi-gigabit speeds. Whichever you order, design in backup connectivity on a different network from the start; a site that justifies a gigabit of dedicated capacity cannot usually afford to be offline while it is repaired.