1. What is Availability Percentage?

The Availability Percentage measures the proportion of time a system or resource is operational compared to its total possible operational time. It's a key metric in reliability engineering and service level agreements.

2. How Does the Calculator Work?

The calculator uses the availability percentage formula:

Where:

• \( Available \) — Operational time in hours
• \( Total \) — Total possible operational time in hours

Explanation: The formula calculates what percentage of the total time the system was available.

3. Importance of Availability Calculation

Details: Availability percentage is crucial for measuring system reliability, meeting SLA requirements, and identifying areas for improvement in uptime.

4. Using the Calculator

Tips: Enter available hours and total hours. Both values must be positive numbers, and available hours cannot exceed total hours.

5. Frequently Asked Questions (FAQ)

Q1: What's considered a good availability percentage?
A: "Five nines" (99.999%) is considered excellent, 99.9% is good for many applications, and 95% may be acceptable for non-critical systems.

Q2: How does this differ from reliability?
A: Availability measures uptime percentage, while reliability focuses on frequency and duration of failures.

Q3: Should planned maintenance be included?
A: Typically no - availability calculations usually exclude planned maintenance windows from total time.

Q4: What time period should I use?
A: Common periods are monthly or yearly, but choose what matches your reporting needs.

Q5: How can I improve availability?
A: Reduce downtime through redundancy, faster recovery, preventive maintenance, and robust monitoring.