- Web Development
E-Commerce for Small Businesses: Getting Started
12 Aug, 2025
Calculate allowed downtime at every SLA level, estimate the financial impact of outages, and understand what each “nine” of availability really means for your business.
| SLA Level | Downtime / Month | Downtime / Year | Tier Name | Typical Use |
|---|---|---|---|---|
| 99% | 7h 18m | 3d 15h 36m | Two Nines | Budget hosting, dev/test |
| 99.5% | 3h 39m | 1d 19h 48m | — | Standard broadband |
| 99.9% | 43m 50s | 8h 45m 36s | Three Nines | Business-grade services |
| 99.95% | 21m 55s | 4h 22m 48s | — | Enterprise cloud |
| 99.99% | 4m 23s | 52m 34s | Four Nines | High-availability |
| 99.999% | 26s | 5m 15s | Five Nines | Carrier-grade |
Downtime is calculated as (1 - SLA%) × total hours in the period. Monthly = 730 hours, yearly = 8,760 hours. Actual SLA terms vary by provider. Talk to our network team
Try our other free IT calculators and planning tools.