FTTC Speeds Explained: What Can Your Business Expect?

FTTC is still one of the most widely used business broadband technologies in the UK. Despite the full-fibre FTTP rollout, millions of premises remain on FTTC. Knowing what speed to realistically expect — and what drags it down — is how you set sensible expectations and spot the moment to upgrade.

How does FTTC actually work?

FTTC is a hybrid technology. Fibre runs from the local exchange to the green street cabinet you see on pavements and verges; from there, the signal travels the last stretch over the existing copper telephone pair into your premises. The fibre half is fast. The copper half is the bottleneck.

Copper degrades signal quality over distance. That single fact explains why two businesses served by the same cabinet can see wildly different speeds. Ofcom classifies these part-fibre services as "superfast" rather than full fibre for exactly this reason (Ofcom).

What FTTC speed should you expect by distance?

The copper run length — the distance from your premises to the cabinet — is the primary determinant of FTTC speed. As a rule of thumb, every additional 100 metres of copper shaves bandwidth off the line. The figures below are indicative, drawn from typical UK 2026 provisioning data and assume a copper pair in good condition.

All ranges above are indicative line-length estimates, not guarantees. In older buildings, internal wiring faults, poor extensions, or corroded connections routinely pull speeds below even these numbers.

Why do FTTC upload speeds matter so much for business?

FTTC is asymmetric: it deliberately gives you far more download than upload. For a household streaming video that is fine. For a business, upload is where the pain shows up — it governs calls, backups, and how fast you can send files out.

These workloads all lean on upload bandwidth:

• VoIP calls consume roughly equal bandwidth in both directions
• Cloud backup and file sync (OneDrive, SharePoint, Google Drive) need steady upload
• Video conferencing (Teams, Zoom) uses upload for your outgoing audio and video
• Sending large files to clients or suppliers is capped by upload speed

A typical 80/20 FTTC line copes well for a small team. Push past 20 staff making simultaneous business VoIP calls while running cloud apps, and that 20Mbps upload ceiling becomes a daily operational constraint, not a footnote.

FTTC vs FTTP: how big is the speed difference?

FTTP (full fibre to the premises) removes the copper last mile entirely — fibre runs all the way into your building. Speed is no longer throttled by line length, and it stays consistent no matter how many neighbouring businesses are online at once. Business FTTP products commonly start around 150Mbps and scale to 1Gbps or beyond, with far healthier upload.

The practical takeaway: if FTTP is available at your premises, upgrading is almost always worthwhile. The speed and consistency jump is large and the price gap is often modest. Where FTTP is not yet built, a full-fibre FTTP leased line or a standard business leased line gives you a dedicated, uncontended alternative. The UK is mid-migration to full fibre under the government's Project Gigabit programme (gov.uk).

What can drag your FTTC speed below the estimate?

Quoted FTTC speeds are estimates based on line length. Several real-world factors routinely undercut them, and most are nothing to do with your provider's network.

• Line quality: old or damaged copper pairs carry less bandwidth than new ones
• Internal wiring: ageing in-building telephone wiring degrades performance; a filtered faceplate on the master socket can help
• Cabinet contention: at peak times, heavy use by nearby customers trims speeds marginally
• Router placement and Wi-Fi: a wired connection always beats Wi-Fi on FTTC — test with a cable before blaming the line

When should your business upgrade from FTTC?

FTTC stays adequate for small offices with modest cloud needs — usually up to 10–15 staff depending on workload. Beyond that, the warning signs are consistent and worth acting on early rather than after a bad week of dropped calls.

Upgrade when you see:

• VoIP call quality wobbling, especially during busy periods
• Teams or Zoom calls regularly choppy or dropping
• Mid-morning or early-afternoon slowdowns as usage peaks
• Cloud apps noticeably slower than they should be
• Headcount growth squeezing bandwidth per person

AMVIA assesses your current FTTC performance, models your team's bandwidth, and advises whether FTTP, bonded FTTC, or a leased line is the right next step. One provider, accountable end to end — connectivity and the security that rides on top of it.