A/B Testing Uptime (Monthly) Calculator Examples
Worked examples showing how uptime differences translate into monthly downtime estimates.
These examples use the same downtime logic with different month lengths and availability gaps. They illustrate how to read the estimated minutes difference between a control and variant.
Standard 30-day service comparison
Control at 99.9% uptime versus variant at 99.95% uptime over 30 days.
Input Summary
Control uptime
99.9%
Variant uptime
99.95%
Days in month
30
Calculation Breakdown
- 1Monthly minutes30 * 24 * 6043,200 minutes
- 2Control downtime43,200 * 0.00143.20 minutes
- 3Variant downtime43,200 * 0.000521.60 minutes
- 4Difference43.20 - 21.6021.60 minutes saved
Result Summary
Difference
21.60 minutes saved
A/B Testing Uptime (Monthly) Calculator
The variant is estimated to reduce downtime by 21.60 minutes.
31-day month with a larger improvement
Control at 99.5% uptime versus variant at 99.8% uptime over 31 days.
Input Summary
Control uptime
99.5%
Variant uptime
99.8%
Days in month
31
Calculation Breakdown
- 1Monthly minutes31 * 24 * 6044,640 minutes
- 2Control downtime44,640 * 0.005223.20 minutes
- 3Variant downtime44,640 * 0.00289.28 minutes
- 4Difference223.20 - 89.28133.92 minutes saved
Result Summary
Difference
133.92 minutes saved
A/B Testing Uptime (Monthly) Calculator
The variant is estimated to have 133.92 fewer downtime minutes.
Variant performs worse than control
Control at 99.99% uptime versus variant at 99.95% uptime over 28 days.
Input Summary
Control uptime
99.99%
Variant uptime
99.95%
Days in month
28
Calculation Breakdown
- 1Monthly minutes28 * 24 * 6040,320 minutes
- 2Control downtime40,320 * 0.00014.03 minutes
- 3Variant downtime40,320 * 0.000520.16 minutes
- 4Difference4.03 - 20.16-16.13 minutes
Result Summary
Difference
-16.13 minutes
A/B Testing Uptime (Monthly) Calculator
The variant is estimated to add 16.13 minutes of downtime.
How to Read Your Results
Estimated downtime saved is positive when the variant has less downtime than the control.
Variant monthly downtime and control monthly downtime are separate estimates for the same selected number of days.
Uptime difference is expressed in percentage points, not as a relative percentage change.
Use the result as an availability comparison, not as a measure of user experience or experiment significance.
Assumptions & Important Notes
- The entered uptime rates use the same definition of availability.
- Each version is compared over the selected full calendar month.
- All unavailable minutes are counted equally in the estimate.
Related Examples
Frequently Asked Questions
Can I use 28, 29, 30, or 31 days?
Yes. Use the number of calendar days in the month you want to model.
What if the control and variant have the same uptime?
Their estimated downtime difference is zero.
Can this estimate downtime for an API or website?
Yes, provided the uptime values reflect the service and monitoring scope you want to compare.
Does the estimate include partial outages?
Only if they are already reflected in the uptime percentage entered.
Ready to calculate your own result?
Use the live calculator with your own inputs, timing, and preferences.