Uptime Calculator
Enter recorded downtime to calculate the percentage of time a service was available. You can also compare that measured result with an availability target.
Observed uptime
99.861111%
Below the availability target
- Reporting period
- 30 days (2,592,000 seconds)
- Target availability
- 99.9%
- Allowed outage
- 43m 12s
- Measured outage
- 1h
- Budget exceeded by
- 16m 48s
Calculate availability from outage records
Subtract unavailable time from the full reporting duration, divide by that duration, and multiply by 100. For example, 60 outage minutes in a 30-day period leave 43,140 available minutes out of 43,200. The resulting uptime is approximately 99.861111%.
Enter incident durations in minutes, using decimals for shorter interruptions: 30 seconds is 0.5 minutes. The total cannot exceed the reporting window. If you need to measure a specific calendar month, use its actual day count through the custom-period option.
Compare the budget with measured outages
The target field does not change measured uptime. It adds a comparison: your outages either fit within the allowance or exceed it. A 99.9% target over 30 days permits 43 minutes and 12 seconds, so the one-hour example misses that target by 16 minutes and 48 seconds.
Count overlapping incidents only once when measuring time unavailable. A service-level agreement may exclude maintenance windows or define availability through successful requests instead of elapsed time. Apply those contract definitions before entering totals. This calculator performs time-based arithmetic; it neither monitors a website nor determines whether a service credit is owed.