Service Level Agreements (SLA): What Uptime Guarantees Mean
A Service Level Agreement (SLA) is a contractual commitment about the performance and availability of a service. Understanding what SLAs mean — and what they don't — helps you have realistic conversations about reliability requirements and what achieving them costs.
Uptime Percentages Explained
| SLA | Annual downtime | Monthly downtime |
|---|---|---|
| 99% | 87.6 hours | 7.3 hours |
| 99.9% | 8.76 hours | 43.8 minutes |
| 99.95% | 4.38 hours | 21.9 minutes |
| 99.99% | 52.6 minutes | 4.4 minutes |
| 99.999% | 5.26 minutes | 26 seconds |
What SLAs Don't Cover
Most SLAs exclude: scheduled maintenance windows, failures caused by the customer's actions, third-party service failures, force majeure events. Cloud provider SLAs (AWS, Azure, GCP) commit to specific percentages but remediation is typically credits — not compensation for lost business.
SLA vs SLO vs SLI
- SLI (Service Level Indicator): A specific metric — availability percentage, 95th percentile latency
- SLO (Service Level Objective): An internal target for an SLI — what you aim to achieve
- SLA (Service Level Agreement): A contractual commitment — a subset of SLOs that carry commercial consequences
Our Commitments
Our standard managed hosting achieves 99.9% uptime. Higher SLAs require additional architecture investment — multi-region active-active deployments for 99.99%+. We are transparent about what specific uptime targets require in terms of infrastructure investment.