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1---
2title: "Uptime SLA Calculator"
3publishedAt: "2025-11-10"
4author: "Thibault Le Ouay Ducasse"
5description: "Calculate allowed downtime from uptime percentages or determine uptime percentages from actual downtime. Supports multiple reporting periods and SLA tiers."
6category: "Product"
7---
8
9_All calculations assume continuous 24/7 availability requirements._
10
11## Understanding Uptime SLA
12
13Service Level Agreements (SLAs) define the expected performance and availability of your services. Understanding uptime percentages and their corresponding downtime allowances is crucial for maintaining customer trust and meeting compliance requirements.
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15
16Common SLA tiers include 99.9% (three nines), 99.99% (four nines), and 99.999% (five nines), each representing different levels of reliability. For example, 99.9% uptime allows for 8.77 hours of downtime per year, while 99.99% allows only 52.6 minutes annually.
17
18
19This calculator helps you understand the real-world impact of your SLA commitments and plan for capacity, incident response, and stakeholder expectations.