Free Tool
SLA Uptime Calculator
Convert SLA percentages (99%, 99.9%, 99.99%) into allowed downtime minutes per year, month, and day.
Allowed downtime for 99.9% SLA
8.76 hours
Per Year
43.80 minutes
Per Month
1.44 minutes
Per Day
8.76 hrs
Total Hours/Year
Tip: Most uptime monitoring tools check every 1-5 minutes. For 99.99%+ SLA requirements, consider Better Stack or Site24x7 with 30-second checks.
Compare uptime monitoring tools →How to use the SLA Uptime Calculator
- Select your SLA tier. Choose a standard SLA percentage such as 99%, 99.9%, 99.95%, or 99.999% (five nines).
- View allowed downtime. Instantly see the maximum allowed downtime per year, month, week, and day for that SLA.
- Compare tiers. Compare different SLA tiers side-by-side to understand the trade-offs for your business.
How this calculator works
Formula
- Allowed downtime (min/yr) = (100 − SLA%) ÷ 100 × 525,600
- Per month = min/yr ÷ 12
- Per day = min/yr ÷ 365
- Hours/yr = min/yr ÷ 60
Inputs
| Input | Unit | Default |
|---|---|---|
| Select SLA Level | % | 99.9% (Three 9s); options 99, 99.9, 99.95, 99.99, 99.999 |
Outputs
- Per Year:
- Minutes/year = (100 − SLA) ÷ 100 × 365 × 24 × 60
- Per Month:
- Minutes/year ÷ 12
- Per Day:
- Minutes/year ÷ 365
- Total Hours/Year:
- Minutes/year ÷ 60, shown to 2 decimals + " hrs"
Assumptions
- 365-day year (525,600 minutes); leap years ignored
- A month is 1/12 of a year (≈30.42 days), not a calendar month
- Durations under a minute are shown in seconds, under an hour in minutes, otherwise in hours
Worked example
Inputs: SLA 99.9% (default)
Result: Per Year 8.76 hours; Per Month 43.80 minutes; Per Day 1.44 minutes; Total Hours/Year 8.76 hrs
Results are estimates from the inputs you provide and the assumptions above, not financial advice.