Calculator input form
Enter your monitoring window, downtime, outage count, and target availability.
Formula used
The calculator converts every entered time unit into minutes first.
Uptime % = ((Total Time − Downtime) ÷ Total Time) × 100
Downtime % = (Downtime ÷ Total Time) × 100
Allowed Downtime = Total Time × (1 − SLA Target ÷ 100)
MTTR = Total Downtime ÷ Number of Outages
MTBF = Total Uptime Time ÷ Number of Outages
Month calculations use 30 days. Year calculations use 365 days.
How to use this calculator
- Enter the full monitoring period value.
- Select the matching unit for that period.
- Enter total downtime across the same window.
- Add the outage count and SLA target.
- Press calculate to view metrics, graph, and exports.
Example data table
These sample rows show how different outage patterns affect uptime.
| Scenario | Monitoring Window | Downtime | Outages | Calculated Uptime | SLA Outcome |
|---|---|---|---|---|---|
| Regional ecommerce site | 30 days | 12 minutes | 2 | 99.9722% | Above 99.9% |
| Internal business portal | 14 days | 95 minutes | 4 | 99.5288% | Below 99.9% |
| API monitoring cluster | 7 days | 3 minutes | 1 | 99.9702% | Above 99.95% |
| Annual hosted platform | 365 days | 300 minutes | 9 | 99.9429% | Below 99.99% |
Frequently asked questions
1. What is website uptime?
Website uptime is the percentage of time a site stays reachable during a measured window. Higher percentages mean fewer interruptions and better service reliability.
2. Is uptime different from availability?
Teams often use both words interchangeably. In practice, availability usually reflects real user access, while uptime focuses on measured operating time during the selected period.
3. What does 99.9% uptime actually mean?
A 99.9% result allows only a small amount of downtime. Over 30 days, that equals about 43.2 minutes unavailable.
4. Why is MTTR useful?
MTTR shows average repair time per outage. Lower MTTR means incidents are restored faster, reducing business impact and improving trust.
5. Why is MTBF important?
MTBF estimates average operating time between outages. Larger values usually indicate stronger stability, better monitoring, and fewer repeated failures.
6. Can I enter months or years?
Yes. This calculator converts minutes, hours, days, weeks, months, and years into the same internal time base before computing every metric.
7. What happens if outages are zero?
The uptime percentage still calculates normally. MTTR and MTBF need incident counts, so they appear as unavailable when outage count is zero.
8. Why export CSV or PDF reports?
CSV works well for spreadsheets and audits. PDF is useful for management summaries, tickets, vendor reviews, and client reporting.