Downtime cost calculator
See what an outage actually costs — based on your real revenue, how long it lasted, and how much of that revenue was lost rather than just delayed.
Enter your revenue per hour, the outage duration, and what share of that revenue is genuinely lost rather than recovered once things come back up. The calculator adds any extra incident costs on top for a total figure.
Downtime cost calculator inputs and results
How this calculator works
Revenue per hour multiplied by outage duration gives the maximum revenue exposed to the incident — what you'd lose if every dollar of revenue during that window disappeared entirely. Multiplying by the loss percentage scales that down to what's realistically gone for good, since plenty of businesses see revenue come back once service is restored rather than vanishing outright.
Extra costs are kept separate rather than folded into the revenue figure, since they're a different kind of cost entirely — money actually spent, rather than money not earned. Keeping them apart makes it easier to see which lever matters more for your specific situation: shortening the outage, reducing the revenue actually lost during it, or controlling the incident response cost itself.
About this tool
This tool is a free calculator. Inputs: revenue per hour, outage duration in hours, percentage of that revenue actually lost rather than delayed, and any extra cost per hour (overtime, SLA penalties). Output: total cost of the outage, split into lost revenue and extra costs. Formula basis: revenue per hour multiplied by the loss percentage multiplied by duration, plus extra cost per hour multiplied by duration.
Frequently asked questions
How is the cost of downtime calculated?
Revenue per hour is multiplied by the outage duration to get the maximum revenue exposed, then multiplied again by the percentage of that revenue actually lost rather than just delayed. Any extra per-hour cost, such as staff overtime or SLA penalty payments, is calculated separately and added on top.
Why does the calculator ask what percentage of revenue is actually lost?
Not all downtime costs the same per hour, even at the same revenue rate. An e-commerce checkout outage usually loses a sale outright — the customer leaves and may not come back. A SaaS outage often doesn't lose the sale at all, since most customers are on subscriptions and still pay, even if they're annoyed. The real cost there is closer to support time, SLA credits, and churn risk than to lost revenue itself, which is why this field exists rather than assuming all revenue during an outage is lost.
What counts as "extra cost per hour"?
Anything that costs money specifically because of the outage, beyond lost sales — incident response staff time and overtime, SLA penalty payments owed to customers, expedited vendor support, or emergency infrastructure costs. Leave it at zero if you only want to see lost revenue in isolation.
Does this account for reputational damage or customer churn after the incident?
No. This calculator only totals the direct, immediate cost of the outage itself. Customers leaving after a bad experience, negative press, or a dip in new sign-ups in the weeks following an incident are real costs but aren't included here, since they depend heavily on factors this tool has no way to estimate.