SLA Availability to Allowed Downtime

Features

• One figure yields the allowed downtime for year, month, week and day
• Readable durations (8 h 45 min 58 s), so you do not convert seconds by hand
• Shows the number of nines (99.9% is three nines)
• The basis is written into the result: a year is 365.25 days, a month 30.44 days
• The four periods stay consistent with each other (month = year ÷ 12)
• Handles 0% and 100%; 100% is zero downtime with no division by zero
• Convert several figures at once, each row copyable on its own

How to use

1. Type one or more availability figures (one per line; 99.9 or 99.9% both work)
2. Choose which period the readable line should use (month by default)
3. All four periods appear immediately
4. Use the copy button on a row to take a single value

FAQ

Why does another tool give a different monthly figure?

Because "a month" has no single definition. This tool uses 30.44 days (365.25 ÷ 12); others use 30 days. For 99.9% that is 43 min 50 s versus 43 min 12 s. Both are found online; the important thing is knowing which one a tool uses, so the basis is written into the result here.

How many nines is 99.9%?

Three nines. The phrase comes from counting the 9s: 99.9% has two in the integer part and one in the decimal part. It is a shorthand for an availability tier; 99.95% also counts as three nines, and 99.99% is four.

What does 100% produce?

Zero downtime — the allowed downtime is 0 for all four periods. The tool writes "zero downtime" rather than going through 1 − 100%, a path that hides a division-by-zero risk even though the result would be 0.

Why not use a 365-day year?

For consistency of the month = year ÷ 12 relation. If the year were 365 days but the month 365.25 ÷ 12, twelve months would exceed a year and the four rows could not be compared side by side. This tool uses 365.25 days throughout.