What does an hour of IT downtime actually cost your business?

Ask a business owner what an hour of downtime costs and you usually get a shrug. Ask them what a new laptop costs and they will tell you to the pound.

That gap is the whole problem. IT spending gets scrutinised because it appears on an invoice. Downtime does not appear anywhere. It shows up as a quiet, expensive afternoon that nobody writes down, and because nobody writes it down, it never gets weighed against the cost of preventing it.

So it is worth doing the sum once.

The simple version

Take your staff, multiply by their average hourly cost, multiply by the hours you were down.

Forty people at £22 an hour, offline for four hours, is £3,520. Do that once a month and it is £42,000 a year, which is more than most small businesses spend on IT support in total.

That number always surprises people, and the reaction is usually the same: "but they weren't doing nothing." Which is fair, and worth taking seriously.

The honest version

Nobody sits with their hands folded for four hours. People make tea, catch up on paperwork, have the conversation they had been putting off. Some work carries on.

But not much, and not for long. Most businesses now have almost everything behind a login: the CRM, the accounts package, the shared files, the phone system, the card machine. When the connection goes, the list of things people can usefully do without it is short, and it runs out after about half an hour.

That is why our calculator has a slider for how much work actually stops. Set it to 100% and you get the theoretical maximum. Set it to 60% and you get something closer to a bad morning where some people can improvise. Most real outages land between 60% and 90%, and using a realistic figure matters, because a number that is obviously inflated gets dismissed by the person you are trying to convince.

What the sum leaves out

Wages are the easiest part to calculate and the smallest part of the cost.

Lost revenue. If you take orders, bookings or payments, an outage is not just idle staff, it is trade that goes elsewhere. A hospitality business with a card machine down on a Friday night is not losing wages, it is losing the night.

Catching up. Work does not disappear, it moves. The four hours you lost on Tuesday become overtime on Thursday or a deadline missed on Friday.

Contractual exposure. Plenty of businesses have their own service commitments to clients. An outage that stops you meeting them can cost you credits, or a contract.

Reputation. Hard to price and easy to underestimate. Telling a client you cannot access their file today is a small thing that gets remembered.

None of that can honestly be estimated from three numbers, which is why our calculator does not try. What it gives you is the floor. The real figure is higher, always.

Work out your own number

Use the IT Downtime Calculator

Three inputs: how many staff are affected, their average hourly wage, and how long a typical outage lasts. It shows you the cost per hour, the cost of a full working day, what it comes to annually if that happens monthly, and what share of your payroll you are spending on people who cannot work.

It takes about thirty seconds and the answer appears on screen. No email, nothing sent to us.

What to do with the number

The point of costing downtime is not to frighten anyone. It is to make a comparison possible.

Once you know that an outage costs you £3,500, questions that felt like expensive extras become straightforward arithmetic. A second internet connection with automatic failover, at maybe £40 a month, pays for itself if it prevents one outage every two years. Proper monitoring that catches a failing disk before it fails is the same conversation. So is a support contract with a guaranteed response time rather than a best-efforts promise.

That last one is worth being specific about. Most IT companies publish an average response time. An average tells you what usually happens. We publish a contractual guarantee: fifteen minutes for a critical issue, backed by service credits if we miss it, alongside a 99.99% uptime guarantee. The difference only matters on the day it matters, which is precisely the day you cannot afford an average.

The uncomfortable follow-up question

Once you have your hourly figure, ask a second one: how long would it take us to get back if the worst happened?

Not a network blip. A failed server, or ransomware, or a flooded comms cupboard. Most businesses have never tested this, and the honest answer is often "we don't know", which in practice means days rather than hours.

Multiply your hourly cost by "a few days" and the case for tested backups and a written recovery plan makes itself. We wrote about what that plan should contain in what is an IT disaster recovery plan.

If you would rather have someone look at where your particular risks are, our free IT health check covers resilience, backups and single points of failure, with no obligation. Or start with the calculator and see what your number looks like.