Downtime Cost Calculator
Updated .
This calculator prices an outage from your own figures: the staff who cannot work, what an hour of their time costs, the share of their productivity that is lost, the revenue that stops, how many hours it lasts and any one-off recovery cost. It shows the cost per hour and the total, and every line of arithmetic. The page supplies only the formula.
How it works
The calculator uses four lines of arithmetic, all shown in the result so you can repeat them on paper:
- Lost staff time = staff affected × loaded hourly cost × (productivity lost ÷ 100) × hours.
- Revenue that stops = revenue (or gross margin) per hour × hours.
- Running cost of the outage = lost staff time + revenue that stops. Dividing by the hours gives the cost per hour.
- Total = running cost + one-off recovery and other costs.
Where the numbers come from. The loaded hourly cost comes from payroll. The productivity lost is a judgement: ask each team what they could still do offline. Revenue per hour comes from your sales records for a comparable period. One-off costs are the ones that do not scale with time, such as outside responders or replacement equipment.
What the total leaves out. It does not include harder-to-price costs such as lost customers, damaged trust, regulatory exposure or the time it takes to catch up afterwards. Treat the result as a floor you can defend, not a ceiling. Pairing it with the restore time estimator turns a restore time into a cost, and the recovery-time planning guide explains how to turn the answer into a number the owner can approve. NIST’s contingency planning guidance describes the same idea as a business impact analysis.
Worked example
Suppose, as a hypothetical, 25 people are affected, each costing $40 an hour loaded, with 60% of their productivity lost, for an outage of 8 hours. Revenue that stops is $500 an hour and one-off costs are $3,000.
Lost staff time: 25 × 40 × 0.60 × 8 = $4,800. Revenue that stops: 500 × 8 = $4,000. Running cost: 4,800 + 4,000 = $8,800, which is $1,100 an hour. Total: 8,800 + 3,000 = $11,800.
If the same outage lasted 24 hours, the running cost would be $26,400 and the total $29,400. That gap is the argument for a shorter recovery plan. These numbers are illustrative arithmetic, not data about any business or incident.
Frequently asked questions
What should I use for loaded hourly cost?
Take wages plus the employer costs that go with them, such as payroll taxes and benefits, from your payroll records, and divide by the hours worked. Use your own figure rather than an industry average.
Should I use revenue or gross margin?
If lost sales would also have saved you the cost of making them, gross margin is the fairer figure. If you cannot recover the sale at all and your costs continue, revenue is closer. Pick one and say which you used.
Does the total include reputational damage?
No. It covers staff time, stopped revenue and the one-off costs you enter. Lost customers, trust and regulatory exposure are real but hard to price, so treat the result as a floor.
How long should I assume an outage lasts?
Try a few values. The restore time estimator and a real restore test give a more honest number than a guess; the cost at 4, 24 and 72 hours is often more useful than one answer.
Does this send my numbers anywhere?
No. The calculation runs in your browser and nothing is stored or sent.
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