Error Budget Calculator

An SLO is a promise; the error budget is what's left of it. Enter your target, your window, and the downtime you've taken so far, and see where you stand.

How to read the numbers

Burn rate is the consumption speed relative to a perfectly even spend. At burn rate 1.0 you land exactly on budget when the window closes. At 2.0 you run out halfway through. Google's SRE workbook suggests paging on sustained burn rates above 2, and treating anything above 10 as an emergency, since a 14x burn rate exhausts a 30-day budget in roughly two days.

One thing this calculator can't know: how the downtime was distributed. A budget burned by a single 12-minute outage and a budget burned by 144 five-second blips look identical here, but they call for different fixes. The first is usually an incident response problem, the second an infrastructure one.

Where the budget actually goes

In practice a chunk of every error budget is spent before mitigation even starts, on detection and escalation. If your checks run every 5 minutes and the first alert sits unread in an inbox for another 10, a 99.9% monthly budget is a third gone before anyone has typed a single command. Tightening check intervals and making alerts impossible to miss is often the cheapest budget recovery available.