Downtime to Uptime Calculator

Calculate your service’s true availability percentage based on total downtime minutes. Enter the duration of downtime and the time window (in days) to convert incidents into an exact uptime figure.

This calculator is built for SREs, engineers, and operations teams who track outages directly. It turns raw downtime into a measurable availability percentage—perfect for reporting, SLA reviews, and internal reliability metrics.

FAQ: Downtime & Uptime Percentage Calculations

1) Why calculate uptime based on downtime instead of the other way around?
Because downtime is often what gets logged during incidents. If you track actual downtime minutes, it’s easy to back into your true availability without relying on vague monthly reports or inflated vendor numbers.

2) What’s the total number of minutes in a month or year?
There are 43,200 minutes in a standard 30-day month and 525,600 minutes in a 365-day year. The calculator uses your selected period (in days) to determine how much downtime impacts your availability percentage.

3) How accurate is this calculation?
It’s a direct conversion based on simple math: total uptime minutes divided by total minutes in the period. It’s accurate as long as your input downtime is accurate, and this is where external monitoring like Dotcom-Monitor can help.

4) What’s considered acceptable downtime?
That depends on your SLA. At 99.9%, you’re allowed about 43 minutes per month. The calculator helps you determine whether you’re within budget or slipping below your threshold.

5) How can I turn this into a report?
The calculator isn’t really set up for this, though you can do it manually. However, Dotcom-Monitor offers downloadable reports and dashboards with exact downtime logs you can back into these same calculations automatically.