SLA Uptime Calculator

What is the SLA Uptime Calculator?

Three nines (99.9%), four nines (99.99%), five nines (99.999%) — these shorthand terms define the SLA tiers that separate good infrastructure from great infrastructure. While three nines allows roughly 8 hours and 45 minutes of downtime per year, four nines permits only about 52 minutes, and five nines a mere 5 minutes and 15 seconds. This calculator instantly converts any SLA uptime percentage into allowed downtime across four time periods: yearly, monthly, weekly, and daily — displayed simultaneously in hours, minutes, and seconds. It is an essential tool for comparing cloud vendor SLAs (AWS, GCP, Azure), reviewing contracts before signing with external providers, planning incident response strategies (RTO/RPO), and designing infrastructure architectures that meet availability targets. All calculations run entirely in your browser — no data is ever sent to any server, ensuring complete privacy.

Common Use Cases

How to Use

1. 1
   Enter SLA Value

   Type your SLA uptime percentage into the input field. You can enter values with multiple decimal places like 99.9, 99.99, or 99.999. Values are automatically clamped between 0 and 100.
2. 2
   Use Quick Select

   Click one of the four preset buttons — 99%, 99.9%, 99.99%, or 99.999% — to instantly fill in a standard SLA value and see results calculated in real time.
3. 3
   View Results

   Four cards display your allowed downtime for yearly, monthly, weekly, and daily periods simultaneously in hours, minutes, and seconds. Viewable at a glance on both desktop and mobile.
4. 4
   Share Results

   Use the sharing buttons at the bottom to copy the result link and share it with teammates or clients, or post it on social media to use as a reference point for infrastructure planning discussions.

Frequently Asked Questions