SLA Downtime Calculator
Convert any SLA uptime percentage to allowed downtime — annually, monthly, weekly, and daily. Includes 99% to 99.9999% reference table. Free tool for IT, SRE, and DevOps teams.
SLA (Service Level Agreement) uptime percentages look small on paper, but the allowed downtime they represent can be significant. A "99% uptime" SLA still permits 87+ hours of downtime per year. Our SLA Downtime Calculator converts any uptime percentage into allowed downtime — annually, monthly, weekly, and daily. Essential for IT teams, SREs, DevOps engineers, and business stakeholders negotiating or monitoring cloud, hosting, or SaaS service agreements.
Formula
Downtime = Total Period × (1 − Uptime % / 100)
Example: Annual downtime for 99.9% SLA = 525,600 minutes × 0.001 = 525.6 minutes = 8 hours 45 minutes
SLA Uptime Reference Table
| SLA Uptime | Annual Downtime | Monthly Downtime | Weekly Downtime | Daily Downtime |
|---|---|---|---|---|
| 99% (two nines) | 87h 39m | 7h 18m | 1h 41m | 14m 24s |
| 99.5% | 43h 50m | 3h 39m | 50m 36s | 7m 12s |
| 99.9% (three nines) | 8h 45m | 43m 49s | 10m 4s | 1m 26s |
| 99.95% | 4h 22m | 21m 54s | 5m 2s | 43s |
| 99.99% (four nines) | 52m 35s | 4m 22s | 1m 0s | 8.6s |
| 99.999% (five nines) | 5m 15s | 26s | 6s | 0.9s |
| 99.9999% (six nines) | 31.5s | 2.6s | 0.6s | 0.09s |
FAQs
What does five nines uptime mean?
Five nines refers to 99.999% uptime — an SLA standard common in enterprise cloud and telecom services. It allows only 5 minutes and 15 seconds of total downtime per year. Achieving five-nines requires redundant infrastructure, automated failover, rigorous change management, and 24/7 monitoring.
Is 99.9% uptime good enough for a business website?
For most small to mid-sized websites, 99.9% uptime (8h 45m downtime/year) is acceptable. For e-commerce sites processing transactions around the clock, 99.95% or higher is worth the premium. High-traffic platforms, financial systems, and healthcare applications typically require 99.99%+.
What is the difference between uptime and availability?
Uptime measures the time a system is operational. Availability is a broader concept that includes whether the system is also performing within acceptable response time limits. A server might be up but so slow it is effectively unusable — this counts as uptime but not full availability.
What SLA compensation can I claim if a provider breaches their SLA?
Most cloud providers (AWS, Azure, GCP) offer service credits — a percentage of the monthly bill applied as a credit. Typical credits range from 10% (minor breach) to 100% of the affected month's bill for severe outages. SLA credits rarely compensate for actual business losses.
How do I calculate my own system's current uptime percentage?
Uptime % = ((Total Period − Total Downtime) / Total Period) × 100. Track downtime in your monitoring tool (Datadog, PagerDuty, UptimeRobot, etc.) and export incident reports monthly. Compare against your contracted SLA.