Server Uptime Calculator
Estimate availability percentage, downtime, SLA compliance and outage cost for servers, APIs and SaaS services.
Hit Calculate to see uptime zone
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Use the same downtime definition your provider, incident system or customer contract uses.
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Test reduced downtime and a different SLA target without changing your main result.
Calculate your baseline first
Uptime is calculated as ((total period time − downtime) ÷ total period time) × 100. This calculator converts your selected days and downtime into the same unit, then computes availability locally in your browser.
A 99.9% target allows downtime equal to 0.1% of the period. For a 30-day month, that is about 43 minutes and 12 seconds, before any SLA exclusions such as scheduled maintenance.
No. The calculation is client-side only: no API calls, no external data fetches, no localStorage and no analytics are used by this calculator.
Results are local estimates based on the downtime and cost assumptions you enter. They do not replace your monitoring records, contract terms, incident postmortems or legal SLA interpretation. VisionVix accepts no liability for operational, billing or contractual decisions based on this output.