SLA Compliance Calculator
Service Level Agreements (SLAs) define the uptime, response time, and availability commitments a service provider makes to customers. Understanding exactly what your SLA commitment translates to in minutes of allowed downtime per year, month, and week is essential for both technical planning and customer communication. This calculator converts an uptime percentage into concrete allowed downtime periods, computes your actual compliance percentage from real downtime data, and shows whether you have a breach based on your SLA target. It also calculates available minutes per year to help you plan infrastructure capacity and redundancy requirements.
SLA formula
Allowed Downtime/Year = (1 - SLA/100) * 8,760 hours
Allowed Downtime/Month = (1 - SLA/100) * 43,800 minutes
Actual Compliance = (43,800 - Actual Downtime) / 43,800 * 100
Common uptime SLA benchmarks
- 99.0% (two nines): 87.6 hours/year, 7.30 hours/month allowed downtime.
- 99.9% (three nines): 8.77 hours/year, 43.83 minutes/month.
- 99.95%: 4.38 hours/year, 21.92 minutes/month.
- 99.99% (four nines): 52.60 minutes/year, 4.38 minutes/month.
SLA compliance: frequently asked questions
What does 99.9% uptime SLA mean?
A 99.9% uptime SLA (also called three nines) allows a maximum of 8.77 hours of downtime per year, 43.83 minutes per month, or 10.08 minutes per week.
What is the difference between 99.9% and 99.99% uptime?
99.9% (three nines) allows 8.77 hours per year. 99.99% (four nines) allows only 52.60 minutes per year. Each additional nine reduces allowed downtime by a factor of 10, but dramatically increases infrastructure cost.
How is SLA compliance calculated?
SLA compliance = (Total agreed time - Total downtime) / Total agreed time * 100. If you had 5 minutes of downtime in a month with 43,800 total minutes, your compliance is 99.99%.
What happens if I breach an SLA?
SLA breach consequences depend on the contract. Typical remedies include service credits (a percentage refund of fees for the affected period), formal incident reports, or in severe cases, right to terminate the contract.
What is a realistic uptime target?
For most SaaS applications, 99.9% (three nines) is a common and achievable standard. 99.95% or 99.99% requires significant investment in redundancy, failover, and geographic distribution.
Sources
- National Institute of Standards and Technology (NIST): Contingency Planning Guide for IT Systems.
- U.S. Federal Trade Commission: Business Guidance Resources.
Reviewed by the CalculatorHub team, edited by James Graham, 14 June 2026. See our methodology.