Uptime Calculator
Calculate SLA requirements and downtime costs
Uptime Target
Business Impact
Allowed Downtime
Cost Impact
SLA Level Comparison
When to Use Uptime Calculator
SLA Negotiations
Client wants 99.99% uptime but your infrastructure supports 99.9%. Show them the cost difference: 4 minutes vs 43 minutes downtime monthly. Sometimes 99.9% is perfectly acceptable once they see the numbers.
Budget Planning
Your e-commerce site makes $10K/hour. One 4-hour outage costs $40K in lost sales. Suddenly that expensive redundant infrastructure doesn't look so pricey. Calculate ROI on reliability investments.
Infrastructure Design
Single server = 99.5% uptime. Load balancer + backup = 99.9%. Multi-region setup = 99.99%. Each level costs more but allows less downtime. Design based on actual business requirements.
Incident Response
System's been down 2 hours. How much of your monthly SLA budget is burned? Calculate remaining allowance to decide if you need emergency escalation or can wait for normal business hours.
Performance Reviews
Team achieved 99.95% uptime this quarter. Sounds great, but that's still 2.6 hours of downtime. Show leadership what different availability levels actually mean in business terms.
Vendor Evaluation
Cloud provider promises 99.95% SLA. That's 4.4 hours downtime yearly. If your business loses $50K per outage hour, factor that into the total cost comparison. Cheapest isn't always best.
Frequently Asked Questions
What is an uptime calculator?
It converts uptime percentages into actual downtime hours. 99.9% sounds great until you realize it's 8+ hours of outages per year. Helps you understand what different SLA levels really mean.
What does 99.9% uptime mean?
8 hours 46 minutes of downtime per year. That's about 43 minutes monthly. Fine for internal tools, might be too much for customer-facing systems. "Three nines" is common for standard business apps.
How much downtime for 99.99%?
52 minutes per year, 4 minutes per month. "Four nines" costs significantly more to achieve but critical for financial systems, healthcare, or high-revenue e-commerce platforms.
How do I calculate downtime costs?
Hourly revenue × downtime hours + recovery costs + reputation damage. E-commerce losing $5K/hour during a 2-hour outage = $10K direct loss, plus customer service costs and future sales impact.
What uptime should I target?
Depends on business impact. Internal tools: 99.5%. Customer apps: 99.9%. Revenue-critical systems: 99.99%. Each level costs exponentially more. Don't over-engineer what you don't need.
Is 100% uptime possible?
No. Even Google and AWS have outages. 99.999% (5 minutes/year) is extremely high availability requiring massive investment. Plan for maintenance windows and unexpected failures.
How accurate are these calculations?
Math is precise, reality varies. Planned maintenance, cascading failures, and recovery time affect actual availability. Use these as planning baselines, not guarantees.
Can I download the results?
Yes. Download button creates an SLA report with uptime targets, downtime allowances, and cost calculations. Perfect for stakeholder presentations and vendor negotiations.
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