Calculate your service downtime percentage with our SLA calculator
| Time | Downtime | Uptime |
|---|---|---|
| Daily | 0.864 seconds | 23 hours 59 minutes 59 seconds |
| Weekly | 6 seconds | 6 days 23 hours 54 minutes 53 seconds |
| Monthly | 26 seconds | 29 days 23 hours 59 minutes 33 seconds |
| Quarterly | 1 minute 18 seconds | 89 days 23 hours 58 minutes 41 seconds |
| Yearly | 5 minutes 15 seconds | 364 days 23 hours 54 minutes 44 seconds |
The downtime calculator shows you exactly how much time your website or server can be unavailable, based on your service level agreement (SLA) percentage. Enter your SLA and the table converts it into the maximum downtime you can expect across daily, weekly, monthly, quarterly, and yearly windows.
Downtime is the share of time a machine — such as a computer or server — is not running or not reachable. It is the inverse of uptime: if a server is available 99.9% of the time, its downtime is the remaining 0.1%. Even a small percentage adds up to real minutes or hours over a year, which is why downtime is usually converted into a duration. This matters most for businesses that depend on reliable, always-on services, such as financial platforms and online stores.
A downtime calculator is a useful tool for checking how much unavailability your SLA actually allows. It turns an abstract percentage into a concrete duration, so you can see exactly how many minutes or hours of downtime you are committing to — or accepting from a provider — over each period.
SLAs are contracts between service providers and users that define the expected level of service. Availability is a key metric in these agreements, and the downtime allowance — the flip side of the uptime percentage — sets the limit on how long a service can be unavailable before the SLA is breached.
Regularly monitoring your downtime helps you catch outages early and check them against your SLA limits. Tracking how much downtime you actually accumulate lets you spot recurring problems and decide whether your current SLA target is realistic.
Downtime can cause significant financial losses and reputational damage, so keeping it within your SLA limit is vital for any business that relies on web services. Knowing your allowance in minutes and hours makes it easier to set alerts, plan maintenance windows, and hold providers accountable.
Also check out these related tools: Uptime calculator, Downtime calculator, SLA calculator, Three-nines, Five-nines.
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