SLA Calculator — Uptime & Downtime (24/7 + Business Hours)
Convert uptime percentages to downtime hours instantly • Compare multiple SLA levels • Calculate business hours availability
1 Custom Calculator
Enter a value between 0 and 100
Enter the total downtime amount to see what uptime % it represents across different periods
Example: 1h 30m = 93.75% daily uptime, 99.11% weekly uptime
Enter up to 4 uptime percentages to compare their allowed downtime and uptime durations
Compare different SLA levels side by side
Calculate uptime based on business hours, working days, or custom schedules
Example: 8h/day, 5 days/week = 40h working time per week
Allowed Downtime
Uptime Duration
Uptime Comparison
2 Calculation Formulas
Period Calculations
Period seconds × (100 – uptime%) ÷ 100
Day: 86,400s | Week: 604,800s | Month: 2,592,000s
Downtime Formula
Downtime = Total seconds × (downtime%)
Example: 86,400 × 0.1% = 86.4 seconds = 1m 26s
Uptime Duration
Uptime = Total seconds – Downtime seconds
Quarter: 7,776,000s | Year: 31,536,000s
3 Industry Benchmarks
Understanding SLA Calculations and Uptime Requirements
Service Level Agreements (SLAs) are critical business contracts that define the expected performance and availability of services. Our SLA calculator helps you understand the real-world impact of different uptime percentages by converting them into tangible downtime periods.
What is SLA Uptime and Why Does It Matter?
SLA uptime represents the percentage of time a service remains operational and accessible. Even small differences in uptime percentages can have significant impacts on your business operations:
- 99% uptime allows 3.65 days of downtime per year – suitable for internal tools
- 99.9% uptime allows 8.77 hours of downtime per year – standard for most web services
- 99.99% uptime allows 52.6 minutes of downtime per year – enterprise-grade reliability
- 99.999% uptime allows 5.26 minutes of downtime per year – mission-critical systems
How to Use Our SLA Calculator
Our comprehensive SLA calculator offers four powerful calculation modes:
SLA % → Hours/Minutes
Enter an uptime percentage to see allowed downtime across all time periods. Perfect for understanding the impact of different SLA levels.
Hours/Minutes → SLA %
Input actual downtime duration to calculate the corresponding uptime percentage for different periods.
Compare Multiple SLAs
Side-by-side comparison of up to 4 different SLA levels to help you choose the right availability target.
Business Hours SLA
Calculate SLA based on your actual business hours rather than 24/7 availability requirements.
Business Hours vs 24/7 SLA Calculations
Many businesses don’t operate 24/7, making traditional SLA calculations misleading. Our business hours calculator considers only your operational time:
- Standard Business Hours: 8 hours/day, 5 days/week (40 hours/week)
- Extended Hours: 12 hours/day, 6 days/week (72 hours/week)
- 24/7 Operations: 24 hours/day, 7 days/week (168 hours/week)
For example, 99.9% uptime during standard business hours allows 2.4 minutes of downtime per week, compared to 10.1 minutes for 24/7 operations.
Industry SLA Benchmarks
Different industries and service types have varying SLA requirements:
| Service Type | Typical SLA | Yearly Downtime |
|---|---|---|
| Internal Tools | 99% – 99.5% | 1.8 – 3.7 days |
| Web Applications | 99.9% | 8.8 hours |
| E-commerce Platforms | 99.95% – 99.99% | 4.4 hours – 53 minutes |
| Financial Services | 99.99% – 99.999% | 53 minutes – 5.3 minutes |
Cost vs. Reliability Trade-offs
Higher uptime requirements typically mean higher costs due to:
- Redundant infrastructure and failover systems
- More frequent monitoring and maintenance
- Faster response times for incident resolution
- Additional staff and on-call coverage
Use our calculator to find the optimal balance between reliability requirements and operational costs for your specific use case.
Related Tools and Resources
Enhance your IT infrastructure management with these complementary tools:
Internal Tools
- Email Header Analyzer – Analyze email delivery and security headers
- RDP Session Calculator – Calculate remote desktop session requirements
- Windows Server Licensing Checker – Ensure server licensing compliance
External Resources
- AWS SLA Documentation – Cloud service level agreements
- Microsoft Azure SLA – Azure service availability guarantees
Frequently Asked Questions
What is an SLA calculator and how does it work?
An SLA calculator converts uptime percentages into allowed downtime periods. It calculates how much downtime is acceptable for different time periods (daily, weekly, monthly, yearly) based on your Service Level Agreement percentage. For example, 99.9% uptime allows 8.77 hours of downtime per year. The calculator uses the formula: Downtime = Total Period Time × (100 – Uptime Percentage) ÷ 100.
What’s the difference between 99.9% and 99.99% uptime?
The difference is significant: 99.9% uptime allows 8.77 hours of downtime per year, while 99.99% uptime only allows 52.6 minutes per year. This represents a 10x improvement in reliability. While 99.9% is suitable for most web applications, 99.99% is considered enterprise-grade availability required for mission-critical systems like financial platforms or healthcare applications.
How do I calculate business hours SLA?
Business hours SLA calculations consider only your operational hours (e.g., 8 hours/day, 5 days/week). Use our Business Hours SLA mode to input your schedule and get accurate downtime calculations based on your actual working time, not 24/7 availability. This is more realistic for businesses that don’t operate around the clock and helps set appropriate expectations with customers.
What SLA percentage should I choose for my service?
The right SLA depends on your service type and customer expectations. Internal tools can often work with 99-99.5% uptime, web applications typically need 99.9%, e-commerce platforms require 99.95-99.99%, and financial services need 99.99-99.999%. Consider the cost of downtime to your business and customers when setting SLA targets.
How is monthly uptime calculated?
Monthly uptime is calculated using a 30-day period (2,592,000 seconds). The formula is: Monthly Downtime = 2,592,000 × (100 – Uptime Percentage) ÷ 100. For example, 99.9% uptime allows 2,592 seconds (43.2 minutes) of downtime per month. Our calculator automatically handles these conversions for all time periods.
Can I convert downtime hours back to uptime percentage?
Yes! Use our “Hours/Minutes → SLA %” mode to input actual downtime duration and see the corresponding uptime percentage for different periods. This is useful when you know how much downtime occurred and want to calculate the achieved SLA percentage for reporting purposes.
What’s the difference between planned and unplanned downtime?
Planned downtime includes scheduled maintenance windows that are communicated in advance, while unplanned downtime is unexpected service interruptions. Many SLAs exclude planned maintenance from uptime calculations, focusing only on unplanned outages. Always clarify in your SLA whether maintenance windows count toward downtime limits.
How do I improve my service’s uptime?
Improving uptime requires multiple strategies: implement redundancy and failover systems, use load balancing, set up comprehensive monitoring and alerting, establish incident response procedures, perform regular maintenance during low-traffic periods, and conduct disaster recovery testing. The specific approach depends on your current architecture and uptime targets.
💡 Tip: Higher uptime percentages mean exponentially less allowed downtime