📈SLA Uptime Calculator

Calculate allowed downtime for 99.9%, 99.99%, and custom SLA percentages.

SLA Uptime %

Allowed downtime at 99.9% uptime (3 nines):

Per Year

8h 45m 57s

Per Month

43m 50s

Per Week

10m 4s

Per Day

1m 26s

About SLA Uptime Calculator

The SLA Uptime Calculator instantly converts any availability percentage into the allowed downtime per day, week, month, and year — making it easy to understand what 99.9% or 99.99% uptime actually means in practice. Use it to evaluate vendor SLAs, set realistic reliability targets, or draft your own service level agreements.

How to Use SLA Uptime Calculator

1
Select or enter your SLA percentage
Choose a common SLA preset such as 99.9% or 99.99%, or type any custom availability percentage into the input field.
2
View the downtime breakdown
Instantly see the maximum allowed downtime per day, week, month, and year for your chosen SLA level.
3
Compare multiple SLA tiers
Add multiple SLA percentages to compare tiers side by side and choose the right level for your product or vendor agreement.

Common Use Cases

DevOps and SRE teams setting reliability targets and error budgets
Business owners evaluating cloud hosting and SaaS vendor SLA promises
Product managers drafting service level agreements for enterprise customers
Sales engineers explaining uptime guarantees to prospective customers

Frequently Asked Questions

What does 99.9% uptime mean in actual downtime?

99.9% uptime (often called 'three nines') allows approximately 8.7 hours of downtime per year, 43.8 minutes per month, and about 10 minutes per week.

What is the difference between 99.9% and 99.99% SLA?

The difference is significant in practice: 99.99% ('four nines') allows only about 52 minutes of downtime per year versus the roughly 8.7 hours allowed by 99.9%.

Can I calculate a custom uptime percentage?

Yes — enter any uptime percentage between 0 and 100 and the calculator will compute the corresponding allowed downtime across all time periods.