Calculated SLA Downtime Result
This result appears above the calculator after submission, as requested.
| Metric | Value |
|---|---|
| SLA target | - |
| Total period time | - |
| Target uptime | - |
| Allowed downtime | - |
| Actual downtime from incidents | - |
| Planned maintenance handling | - |
| Maintenance minutes supplied | - |
| Counted downtime in SLA | - |
| Remaining error budget | - |
| Budget status | - |
| Achieved availability | - |
| Largest equal outage count allowed | - |
SLA Downtime Calculator
The page stays single-column overall. The calculator fields below switch to three columns on large screens, two on smaller screens, and one on mobile.
Example SLA Downtime Table
These examples assume a 30-day month and a 365-day year.
| SLA target | Allowed monthly downtime | Allowed yearly downtime |
|---|---|---|
| 99% | 7h 12m (432.00 min) | 3d 15h 36m (5,256.00 min) |
| 99.5% | 3h 36m (216.00 min) | 1d 19h 48m (2,628.00 min) |
| 99.9% | 43.2m (43.20 min) | 8h 45.6m (525.60 min) |
| 99.95% | 21.6m (21.60 min) | 4h 22.8m (262.80 min) |
| 99.99% | 4.32m (4.32 min) | 52.56m (52.56 min) |
Formula Used
Allowed downtime = Total period minutes × (1 − SLA target ÷ 100)
Target uptime = Total period minutes − Allowed downtime
Counted downtime = Incident downtime + Included maintenance
Achieved availability = ((Total period minutes − Counted downtime) ÷ Total period minutes) × 100
Remaining error budget = Allowed downtime − Counted downtime
Monthly, quarterly, and yearly presets use common fixed assumptions. Contracts may define different month lengths, maintenance exclusions, or measurement windows. Use Override total minutes whenever your agreement uses a custom basis.
How to Use This Calculator
- Enter the service name and target SLA percentage.
- Select a period such as monthly, quarterly, or yearly.
- Use Custom days or Override total minutes if your contract is unique.
- Enter either a manual downtime total or an incident duration list.
- Add planned maintenance and decide whether it counts toward SLA.
- Set an example outage size to estimate how many equal incidents fit.
- Press the calculate button.
- Review the result section above the form, chart, and exports.
Frequently Asked Questions
1. What does SLA downtime mean?
SLA downtime is the maximum unavailable time allowed during a measured service period while still meeting the promised availability percentage.
2. Why does a tiny SLA change matter so much?
Because the remaining error budget becomes very small at high availability targets. Moving from 99.9% to 99.99% cuts allowable downtime dramatically.
3. Should maintenance count against SLA?
That depends on the contract. Some agreements exclude approved maintenance windows, while others count all unavailable minutes. Always confirm the exact wording.
4. Can I use custom contract periods?
Yes. Choose Custom days or supply Override total minutes. That helps when billing cycles, business windows, or reporting periods differ from common calendar assumptions.
5. What is an error budget?
An error budget is the downtime you can still spend before violating the target SLA. Teams often use it to balance reliability and release speed.
6. Why does the calculator show achieved availability too?
It helps compare the current measured outcome with the promised target. This is useful for incident reviews, customer reports, and operational dashboards.
7. Can I export the result?
Yes. After calculation, use the CSV or PDF buttons to save a report-friendly copy of the summary metrics and example reference table.
8. Is this calculator suitable for SLO planning too?
Yes. The same downtime math supports SLO planning, alert policies, and release gating, as long as the measurement window matches your internal rules.