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Utility Calculators

Uptime Percentage Calculator

Verified formula Updated Jun 2026 Private — runs on your device

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hours
hours
Verified formula Private

Uptime percentage

99.7222%

For general information only — not financial, tax, legal or medical advice. Verify before you rely on it.

How to use the Uptime Percentage Calculator

The Uptime Percentage Calculator works out your uptime percentage in an instant. Enter total period and downtime and the result updates as you type — it is free, needs no sign-up, and runs entirely in your browser so your figures stay private.

  1. Enter the total period.
  2. Enter the downtime.
  3. Read off your uptime percentage — the calculator updates automatically, with no button to press.

Formula

The Uptime Percentage Calculator uses the formula:

Uptime percentage = (Total period - Downtime) ÷ Total period × 100

Worked example

For example, with total period of 720 hours and downtime of 2 hours, the uptime percentage is 99.7222%.

Inputs used
Total period 720 hours
Downtime 2 hours
Results
Uptime percentage 99.7222%

Results are estimates for educational use, not professional advice.

Key terms explained

Percentage
A number expressed as a fraction of 100, written with the % sign.

Frequently asked questions

Subtract downtime from the total period, divide by the total, and multiply by 100. 2 hours down in 720 hours is 99.72% uptime.

99.9% uptime, which allows about 8.76 hours of downtime per year.

It is a core service-level metric; higher uptime means more reliable availability for users.

Multiply the period by (1 − uptime) to find the permitted downtime.

Enter the total period. Enter the downtime. Read off your uptime percentage — the calculator updates automatically, with no button to press.

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