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Uptime SLA Calculator

Developer Tools

Availability percentage to allowed downtime per year

Quick Answer

Uptime SLA Calculator: Availability percentage to allowed downtime per year. Allowed downtime = (1 − availability) × period.

Service level

%
Per year8.76 h(526 min)
Per month43.8 min
Per week10.1 min

How it works

  1. 1Year ≈ 525600 min, month 43800, week 10080
  2. 2Downtime = (1 − 99.9%) × period = 525.6 min/yr
  3. 3Each extra nine cuts allowed downtime 10× — and multiplies cost
Compute your error budget before promising SLAs: 99.9% allows ~44 min of full outage monthly. Excluding maintenance windows and driving releases by error budget works better.

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How to Use

  1. Paste or type content: drop code/text into the Uptime SLA Calculator or fill the parameters.
  2. Choose mode/options: switch format, rules or processing as needed.
  3. Live output: results appear instantly — nothing is submitted, data stays in your browser.
  4. One-click copy: copy the output straight into your development environment.

Key Points

  • Uptime SLA Calculator is a free online developer tool — open and use, no sign-up.
  • All calculations run locally in your browser; your data never leaves the device.
  • Key capability: Availability percentage to allowed downtime per year.
  • Results come with formulas and reference tables so you can verify every number.

Formula & How It Works

Uptime SLA → allowed downtime

Allowed downtime = (1 − availability) × period
99% → 3.65 days/yr; 99.9% → 8.77 h/yr; 99.95% → 4.38 h/yr; 99.99% → 52.6 min/yr; 99.999% → 5.26 min/yr
Each extra nine cuts allowed downtime 10×
Achieve it with multi-AZ, health-checked failover, canary deploys, DB replicas

Example: 99.95% SLA → 0.05% × 525,600 min ≈ 262.8 min/yr ≈ 21.9 min/month.

FAQ

How do I use the Uptime SLA Calculator?
Open the page and fill in the input fields — results update automatically. Availability percentage to allowed downtime per year.
Are the results accurate?
Yes. Standard formulas and conversion factors are used and verified.
Is it free? Do I need to sign up?
Completely free. No registration, login or download required.
Does it work on mobile?
Yes. The responsive design works on phones, tablets and desktops.
Is my data saved?
No. Everything runs locally in your browser.

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Source & Updates

Based on RFC 4648, ECMA-262 and related specifications. Last updated: 2025-07

Last updated:

Formulas and content on this page are reviewed by the YiJianSuan team. For reference only — official sources prevail.

Maintained and periodically reviewed by the YiJianSuan editorial team — review process in ourEditorial Policy.

Cite this page: YiJianSuan. Uptime SLA Calculator[EB/OL]. https://www.yijiansuan.com/en/c/dev/uptime-sla

Results provided by this tool are for reference only and do not constitute professional advice.