# Uptime and Downtime Calculator (SLA)

URL: https://speedycalculator.com/calculators/other/uptime/
Last updated: 2026-10-25

> The uptime calculator converts an availability percentage, such as 99.9%, into the allowed downtime per day, week, month and year, as used in service level agreements.

## Inputs

- Availability (%)

## Results

- Downtime per year
- Downtime per month
- Downtime per week
- Downtime per day

## Formula

```
Downtime = (1 − availability) × period
```

## Explanation

Each extra “nine” cuts allowed downtime by a factor of ten: 99.9% allows about 8.8 hours a year; 99.99% allows about 53 minutes.

### How to use the Uptime and Downtime Calculator

- **Availability**

Results update as you type, and every field accepts the units shown in its menu.

### How it works

The unavailable fraction is multiplied by the length of each period.

### What each result means

- **Downtime per year** = (1 - [Availability]÷100)×31557600
- **Downtime per month** = (1 - [Availability]÷100)×2629800
- **Downtime per week** = (1 - [Availability]÷100)×604800
- **Downtime per day** = (1 - [Availability]÷100)×86400

## Worked example

Inputs — Availability: 99.9 %.

Results — **Downtime per year = 8:45:58**; Downtime per month = 43:50; Downtime per week = 10:05; Downtime per day = 1:26.

## FAQ

**What is “five nines”?**
99.999%, about 5 minutes 15 seconds of downtime per year.

**Does planned maintenance count?**
It depends on the SLA wording.

**What formula does the Uptime and Downtime Calculator use?**
Downtime = (1 − availability) × period.