IT Downtime Cost for UK Businesses: How to Work It Out
What IT downtime really costs a UK business, where the $5,600-a-minute figure comes from, and a simple formula to work out your own hourly cost.
Nerdster Team
Most firms underestimate what IT downtime costs them, because they only count the hours their people sat idle.
The real bill is longer. Lost revenue. Missed deadlines. A client who starts taking other calls. A regulatory obligation you could not meet. And the quiet damage of good people deciding your systems are somebody else’s problem to fix.
If you run a UK business where every hour is billable or every transaction is timed, your IT downtime cost is almost certainly higher than the figure in your head. This guide shows you how to work out the real number, what causes the outages, and what actually reduces them.
How much does IT downtime cost a UK business?
There is no reliable UK-wide figure for the cost of an hour of downtime, and the numbers that circulate most widely were not measured on businesses of your size. It is worth knowing where they come from before you quote one.
- $5,600 per minute comes from a 2014 Gartner blog post, which presented it as an average drawn from industry surveys and warned of a large degree of variance either side. It is in US dollars and more than a decade old.
- Over $300,000 an hour comes from ITIC’s 2024 Hourly Cost of Downtime survey of more than 1,000 organisations worldwide. It found an hour cost more than that at over 90% of mid-size and large enterprises, and 41% of enterprises put it at $1 million to over $5 million. Those are enterprise numbers.
- The UK government’s own survey points the other way. In the Cyber Security Breaches Survey 2025/26, the median perceived cost of a business’s most disruptive breach or attack was £0, rising to £30 for medium and large businesses. At the 95th percentile it was £4,000, and £10,000 for medium and large businesses. Most incidents cost little; a minority cost a great deal. And those are perceived costs of cyber incidents, not of every outage.
None of these is your number. Yours depends on who is idle, what you bill, and how long recovery takes.
The money you lose while systems are down
Idle payroll. Take a 40-person firm with a fully loaded cost — salary, benefits, space, overheads — of £80 per hour per person. One hour of full downtime burns £3,200 in wages before anything else happens.
Lost revenue. If you bill for time, downtime removes revenue directly. A professional services firm billing £250 an hour across 40 people loses £10,000 for every hour offline. For a trading desk the figure depends entirely on what the market did while you were down.
Recovery. Getting back up costs money too: emergency support time, specialist data recovery, overtime. A serious ransomware incident is a different order of cost altogether: Sophos’s State of Ransomware 2026 puts the average recovery cost, across the organisations it surveyed, at $1.7 million per incident.
The costs that never reach a spreadsheet
Client damage. Missed deadlines, dead phones, and deliverables that arrive late do measurable harm you cannot itemise. In a competitive market, one visible outage is enough to make a good client curious about alternatives.
Regulatory exposure. FCA-regulated firms carry operational resilience obligations. Downtime that stops you meeting a reporting deadline or executing a client order invites supervisory attention you did not budget for.
Staff retention. IT that fails repeatedly wears people down, and in the London labour market that is a retention risk. It never shows up on a balance sheet and it costs you all the same.
Reputation. Bounced email, a client portal that is down, phones going nowhere — these tell the exact audience you most want to impress that your operation is fragile.
Six causes behind most UK IT downtime
Prevention gets easier when you know what actually breaks. Across the UK businesses we support, six causes come up again and again.
1. Patch before a deferred update takes you offline
Outdated operating systems, unpatched applications, and ageing hardware sit behind a large share of unplanned outages. The critical update deferred “until next week” turns into a crash or a breach that costs far more than the twenty minutes it would have taken.
2. Assume ransomware means weeks, not hours
Ransomware is rarer than most people assume — the Cyber Security Breaches Survey 2025/26 put it at 1% of UK businesses — but when it lands, recovery is measured in days and weeks rather than hours. Even with clean backups, rebuilding an entire environment from scratch is slow work. Plan your continuity around that timescale, not around a best case; our look at ransomware in 2026 covers what the latest data shows.
3. Replace hardware before it fails on a Monday morning
Servers, storage, and network kit all have a finite life. Running critical infrastructure past its vendor support window is a bet, and it gets more expensive to lose every month you hold it.
4. Protect yourself from an honest mistake
Deleted files, a misconfigured cloud service, a change pushed without testing — human error causes a meaningful share of outages. These are usually the quickest to resolve and by far the easiest to design out.
5. Stop one broken line taking the whole office down
If your business runs on cloud services, and yours does, an internet outage is a total outage. Single points of failure in connectivity are surprisingly common across London offices.
6. Keep working when Microsoft 365 has a bad day
Microsoft has outages, and you will not prevent them. What you can control is how much of your operation stops when one happens. Know which processes depend on a single platform, and have a way to keep the essential ones moving.
Five changes that cut IT downtime cost
Detect faults sooner
The gap between a five-minute fix and a five-hour outage can be detection time. Monitoring across servers, endpoints, network kit and cloud services surfaces events without waiting for somebody to raise a ticket. What happens next depends on the quality of the alert and the response process. Ask any prospective IT provider for their average time from alert to resolution, and ask to see it measured.
Proving your backups restore
Having backups is not the same as being able to recover. A real backup and disaster recovery capability includes:
- A recovery time objective — how long you can be down
- A recovery point objective — how much data you can afford to lose
- Restoration testing at least quarterly, done properly
- Written procedures that do not live in one person’s head
A second line costs less than an hour of downtime
Every London office should have a secondary internet connection from a different provider, ideally on different infrastructure — fibre primary, 5G failover. Compare the monthly cost against the hourly cost you calculated above. The maths is not close.
Standardise laptops so faults repeat and resolve fast
Standardising your laptops and workstations on consistent hardware and software cuts the number of different problems you can have. Managed endpoints with automatic patching, EDR, and remote access are faster to diagnose and quicker to fix.
What happens when the systems stop
Document the plan. Who decides? Who tells clients? Can essential work continue on paper for a day? Then test it once a year. Testing the plan, rather than filing it, is the whole difference between a resilient business and a hopeful one.
Calculate your own IT downtime cost in one line
Start here:
Hourly downtime cost = (people affected × average hourly cost) + (hourly revenue at risk) + (expected recovery cost ÷ expected hours down)
Run it for your own business with real numbers. The answer is usually uncomfortable enough to settle the argument about prevention.
Cut the downtime you are already paying for
Our managed IT support is built around keeping you running: monitoring that carries on outside office hours, proactive maintenance, tested disaster recovery and a defined incident response process, with the level of cover agreed with you up front.
If you want to know your current downtime risk and what it would take to reduce it, book a free IT assessment with Nerdster. You will get a clear, quantified picture of where you stand.
