The number is bigger than the obvious math
Ask a business owner what an hour of downtime costs and they’ll often do quick math: an hour divided by daily revenue. That number is real, but it’s usually only part of the actual cost. A more complete calculation includes several things that don’t show up in that first estimate.
Lost revenue is the easy part to calculate
If your business can’t process sales, take orders, or serve customers during an outage, the lost revenue for that window is straightforward to estimate: your typical revenue for that time period, gone. This is usually the number people start with, and it’s real, but it’s rarely the full cost.
Staff time is a cost that’s easy to overlook
During an outage, employees aren’t just idle, they’re often actively trying to work around the problem, checking whether it’s fixed, or handling frustrated customers. That’s paid time not producing normal output. For a team of ten people each earning a modest hourly rate, an hour of disrupted work adds up faster than it seems like it should.
The cost of catching up afterward
Downtime rarely just costs the hour it happens. There’s usually a backlog afterward, orders to process, calls to return, work that piled up while systems were down. This catch-up period extends the real cost well past the outage itself, even though it doesn’t show up as clearly on a timeline.
A more complete way to estimate the cost
| Cost category | How to estimate it |
|---|---|
| Lost revenue | Typical revenue for that time window |
| Idle or disrupted staff time | Hourly cost of affected employees during the outage |
| Catch-up time afterward | Extra hours spent clearing the backlog once systems are back |
| Customer impact | Harder to quantify, but real for repeat business and reputation |
Customer impact is the hardest number to pin down
A customer who can’t reach you, can’t check out, or has a bad experience during an outage doesn’t always come back, and even when they do, the relationship has taken a small hit. This is the least precise part of the calculation, but it’s often the most expensive over time, since it affects future revenue, not just the revenue during the outage itself.
Why this math matters for IT decisions
Once you calculate a more realistic cost per hour of downtime, decisions about backup systems, monitoring, and managed IT support start to look different. A monthly managed IT fee that seemed like a meaningful expense often looks much smaller next to the real cost of even one or two serious outages a year.
A rough exercise worth doing
Take your last real outage, however small, and walk through each of the categories above honestly. Most business owners are surprised by the total once staff time and catch-up work are included, not just the lost revenue during the outage window itself.
Want help estimating what downtime actually costs your business, or reviewing whether your current setup is protecting you from it? Reach out and we’ll help you run the numbers.