Estimate what one outage costs your website in lost revenue, response labor, and direct costs, then see how much faster detection saves per year. Free, no sign-up, and nothing you enter leaves your browser.
Cost of one incident
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The calculator adds three costs for one incident, then multiplies by how often incidents happen:
Revenue per hour = annual online revenue ÷ 8,760
Lost revenue = revenue per hour × (detect + restore minutes ÷ 60) × % affected
Response labor = people × hourly cost × (restore minutes ÷ 60)
Cost per incident = lost revenue + response labor + other direct costs
Annual exposure = cost per incident × incidents per year
Customers feel the outage from the moment it starts, so lost revenue counts both detection and restore time. Responders only start working once someone knows, so labor counts restore time only. The savings figure is the lost revenue from the detection minutes you no longer wait for.
Treat the result as a floor. Dividing annual revenue by every hour of the year assumes revenue is spread evenly, and most sites earn more at peak hours. A checkout outage during a sale costs far more than the same outage at 4 a.m.
For the full worksheet, including campaign waste, SLA credits, and worked examples, read how to calculate website downtime cost.
You control two parts of every outage: how fast you find out, and how fast you fix it. Detection is usually the cheaper one to improve. Here is the same 45-minute fix with different detection times:
| How you find out | Time to detect | Customer-facing downtime |
|---|---|---|
| A customer complains | 30–60 min | 75–105 min |
| 10-minute checks | 10–20 min | 55–65 min |
| 1-minute checks | 1–2 min | 46–47 min |
Detection times are illustrative ranges: one or two check intervals for monitoring, and a typical delay before someone reports a problem. Put your own numbers into the calculator. To compare intervals in depth, see 1-minute vs 5-minute monitoring.
Webalert checks your site, API, and SSL certificate around the clock and alerts you by email, Slack, or SMS the moment something fails. Start free, no credit card.
Hidden costs, worked examples, and how to present low, expected, and high cases.
How much downtime each SLA level allows per year, month, and week.
Check if a site is down for everyone or just you, from outside your network.