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Leased line cost calculator
A leased line costs several times what business broadband costs. Whether it is worth it has almost nothing to do with speed and everything to do with what an hour of downtime costs you. This works out both sides over a full 36-month term.
Leased line vs business broadband, over 36 months
The monthly price is the wrong comparison on its own. What decides it is what an hour of downtime costs you.
If you have no idea, 8 hours is a reasonable starting assumption for a single unresolved fault plus a few short drops.
Often £0 on a 36-month term, but excess construction charges apply where new civils are needed. Ask before you sign.
Business broadband — lower total cost
£4,140
over 36 months, all in
- Line and install
- £2,340
- Cost of downtime
- £1,800
Leased line
£13,320
over 36 months, all in
- Line and install
- £12,600
- Cost of downtime
- £720
Business broadband is probably the better buy
On these numbers the leased line costs about £9,180 more across the term than it saves. It would start to pay for itself at around 76 hours of outage a year. If your actual experience is worse than that, revisit it.
Estimates only, and deliberately simplified. Real leased line pricing depends on your postcode, the distance to the nearest point of presence and whether new civils are needed — which is why an excess construction charge can turn a £0 install into a five-figure one. Downtime modelling assumes a failover cuts effective outage to about a quarter and a contractual SLA to about a tenth; your experience will vary.
Leased lines: common questions
How much does a leased line cost in the UK?+
Typically £200–£600+ a month depending on bandwidth, contract length and your location, against £25–£60 a month for business broadband. Installation is often included on a 36-month term, but excess construction charges apply where new civils are needed — and those can turn a £0 install into a five-figure one, so always ask before signing.
What actually makes a leased line different?+
It is dedicated and uncontended, so you are not sharing capacity with other businesses, and it is symmetric — upload matches download. It also comes with a contractual fix-time SLA rather than best-efforts support. Speed is the least important of those three for most businesses; the SLA is usually what you are really buying.
Is full fibre good enough instead?+
For most single-site small businesses, yes — particularly with a 4G or 5G failover, which costs around £20 a month and keeps card payments and core systems running through most outages. The case for a leased line strengthens when downtime stops trading entirely, when you need guaranteed upload, or across multiple sites on a shared platform.
How long does a leased line take to install?+
Commonly 30–90 working days, against days to a few weeks for business broadband. If a survey finds that new ducting or civils are needed it can take longer. Factor that into any decision tied to a move-in date or an existing contract ending.