Availability percentage shows what proportion of checks found your site operational over a given period.
The calculation
Availability = (Successful checks / Total checks) × 100
Time periods
NerdTools calculates availability for:
- 24-hour — Last day
- 7-day — Last week
- 30-day — Last month
Understanding the numbers
- 99.9% — About 1.4 minutes of downtime per day, or 43 minutes per month
- 99.5% — About 7 minutes of downtime per day, or 3.6 hours per month
- 99.0% — About 14 minutes of downtime per day, or 7.2 hours per month