Last updated: 2026-07-19
What Is an Error Budget?
Definition
An error budget is the amount of "acceptable" unreliability your service can have before you violate your SLO. If your SLO is 99.9% uptime, your error budget is 0.1%: about 43 minutes of downtime per month. The error budget is not a target to use up. It is a constraint: when it runs out, reliability work takes priority over new features.
Why it matters
Error budgets replace arguments about "should we fix this bug or ship this feature?" with data. When you have error budget remaining, ship features. When the budget is exhausted, fix reliability. This is the core operational model of Site Reliability Engineering (SRE). Without monitoring data to track error budgets, you are flying blind.
Example
A payment processing service has an SLO of 99.99% uptime (about 4.3 minutes of downtime per month). In October, a DNS misconfiguration caused 3 minutes of downtime. With 1.3 minutes of error budget remaining, the team decided to freeze all non-critical deploys for the rest of the month and ran a full infrastructure review to prevent recurrence.
How PingWatchdog helps
PingWatchdog tracks every incident with timestamps and duration. Use the incident history to calculate your error budget consumption at any time. Combine uptime check data with your SLO target to know exactly how much budget remains. Export this data to your internal dashboards or SRE review documents.