A/B Testing SLA Target vs Actual Availability
Compare SLA targets with actual monthly availability and see how downtime exclusions and credit caps affect the result.
A monthly A/B testing SLA calculation has several distinct comparisons: target versus actual availability, reported versus chargeable downtime, and an uncapped versus capped credit. Each comparison answers a different operational or contractual question.
- 100% Free
- No Sign-Up Required
- Private & Secure
- Mobile Friendly
About A/B Testing SLA Target vs Actual Availability
A monthly A/B testing SLA calculation has several distinct comparisons: target versus actual availability, reported versus chargeable downtime, and an uncapped versus capped credit. Each comparison answers a different operational or contractual question.
3
Comparisons
5
Key Factors
Instant
Results
100%
Free to Use
Reported downtime vs chargeable downtime
Compare raw incident duration with the downtime that counts toward the monthly SLA.
| Factor | Option A: Reported Downtime | Option B: Chargeable Downtime | What It Means |
|---|---|---|---|
| Definition | All recorded unavailable or materially impaired minutes. | Reported minutes less valid SLA exclusions. | Reported downtime supports incident review, while chargeable downtime is used for the SLA estimate. |
| Maintenance treatment | Includes maintenance if it was recorded as interruption time. | Removes only maintenance explicitly excluded by the SLA. | The SLA result should reflect only qualifying exclusions. |
| Availability calculation | May understate availability if valid exclusions are included. | Represents the calculator's availability input. | Chargeable downtime aligns with the stated formula. |
| Operational impact review | Shows the full observed interruption burden. | Can omit valid excluded events. | A full operational review may need all incident time, regardless of SLA treatment. |
Reported downtime describes what was recorded; chargeable downtime describes what counts against the SLA after eligible exclusions.
Uncapped credit vs capped service credit
Compare the hourly credit estimate before and after the maximum monthly credit rate is applied.
| Factor | Option A: Uncapped Service Credit | Option B: Capped Service Credit | What It Means |
|---|---|---|---|
| Calculation basis | Excess downtime hours multiplied by the entered hourly credit. | The lower of the uncapped credit and the maximum monthly credit. | Both figures are useful, but they answer different questions. |
| Reflects contractual limit | No, it ignores the cap. | Yes, it applies the entered maximum credit rate. | The capped result is the calculator's final estimate. |
| Use during large outages | Shows the size of the hourly-rate calculation. | Shows the amount after the maximum is enforced. | A cap can substantially reduce the final estimated credit. |
| Use in contract review | Helps identify the effect of the per-hour term. | Helps identify the effect of the maximum-credit term. | Reviewing both values makes the two contractual levers visible. |
The uncapped amount shows the hourly-rate result; the capped amount shows the estimate after the stated monthly limit.
99.9% target vs 99.95% target
Compare two common high-availability targets over the same 30-day month.
| Factor | Option A: 99.9% Monthly Target | Option B: 99.95% Monthly Target | What It Means |
|---|---|---|---|
| Permitted downtime in 30 days | 43.2 minutes. | 21.6 minutes. | The stricter target permits half as much downtime. |
| Tolerance for a single 30-minute outage | Within the allowance if there are no other chargeable outages. | Above the allowance. | A less stringent target has a larger monthly downtime allowance. |
| Required reliability level | High availability. | More stringent high availability. | The higher target leaves less room for chargeable interruption. |
| Likelihood of exceeding the allowance | Lower for the same incident history. | Higher for the same incident history. | This is a mathematical result of the larger downtime allowance, not an assessment of service quality. |
A 99.95% target is stricter than 99.9% because it permits fewer downtime minutes in the same month.
Key Differences at a Glance
Actual availability uses chargeable downtime, not necessarily all recorded incident time.
The permitted downtime allowance changes with both the SLA percentage and the number of days in the billing month.
A higher availability target creates a smaller downtime allowance.
An hourly credit rate determines the uncapped estimate, while the maximum credit rate limits the final estimate.
Operational incident impact and contractual SLA treatment can produce different views of the same outage.
How to Decide
Assumptions
- The comparison uses the calculator's proportional method for excess downtime hours.
- Examples of 99.9% and 99.95% targets assume a 30-day billing month.
- Excluded maintenance is treated as valid only when it is allowed by the applicable SLA.
- The comparison is educational and does not determine contractual rights or obligations.
Related Comparisons
Frequently Asked Questions
Is actual availability always lower than the SLA target after an outage?
No. An outage can occur while actual availability remains above the target if chargeable downtime stays within the monthly allowance.
Which downtime figure should be used for the SLA calculation?
Use chargeable downtime: reported downtime less only the exclusions permitted by the agreement.
Why compare uncapped and capped credits?
The comparison shows whether the maximum monthly credit term changes the hourly-rate estimate.
Is 99.95% twice as reliable as 99.9%?
Not in a simple linear sense. For a 30-day month, 99.95% permits 21.6 minutes while 99.9% permits 43.2 minutes.
Does a higher SLA target guarantee a higher service credit?
No. The credit also depends on chargeable downtime, the entered hourly rate, the eligible fee, and the cap.
Ready to calculate your result?
Try the calculator and compare options with your own inputs.