SRE Error Budget Calculator
Calculate error budgets based on SLO targets and actual uptime.
Last reviewed by the Radiatus Cloud team
Want this automated for your stack?
We build CI/CD, Kubernetes & IaC pipelines that scale.
Turn an SLO into an allowance for failure
A service level objective sets a reliability target, say 99.9% uptime, and its complement is the error budget: the amount of unreliability you are allowed before you have missed the target. This calculator works out the error budget from an SLO and compares it against actual uptime, so you know how much room you have left.
Why the budget reframes reliability
An error budget turns reliability from an absolute into a resource to spend. Under a 99.9% objective you are permitted roughly forty-three minutes of downtime a month; if you have used ten, you have thirty-three left to spend on risky deployments or absorb from incidents. When the budget is exhausted, the signal is to slow down and stabilise rather than ship. That framing resolves the usual tension between shipping fast and staying reliable by making the trade-off explicit.
The numbers behind the nines
The gap between 99.9% and 99.99% sounds small but is a factor of ten in allowed downtime, from about forty-three minutes a month to about four. Seeing the actual minutes each objective permits is what makes an SLO a real decision rather than a slogan. The calculation runs in your browser.
Related tools
- CI/CD Security Gap Analyzer — Checklist based analyzer for CI/CD pipeline security gaps.
- Docker Security Scanner — A new tool extracted from the codebase.
- Terraform Scanner — A new tool extracted from the codebase.
- SQL Formatter — Format and indent SQL queries for readability. Handles joins, subqueries and CTEs, supports common dialects, and runs entirely in your browser.
Frequently Asked Questions
What is an error budget?
The amount of unreliability an SLO permits: the complement of the target. A 99.9% objective allows 0.1% downtime, which is the budget you can spend before missing the target.
How much downtime does 99.9% allow?
Roughly forty-three minutes a month. Moving to 99.99% cuts that to about four minutes, a tenfold reduction for one extra nine.
What happens when the budget is exhausted?
The signal is to slow down and prioritise stability over new features until reliability recovers, rather than continuing to spend a budget you no longer have.
Why frame reliability as a budget?
Because it makes the trade-off between shipping fast and staying reliable explicit: risky changes spend the budget, and incidents consume it, so the decision becomes concrete.
Is my data uploaded?
No. The calculation runs entirely in your browser.
Privacy & Security
Calculations are local.
About This Tool
This tool runs entirely in your browser. No data is sent to any server, ensuring complete privacy. Simply use the interface above to get started — no registration or login required.
Disclaimer: This tool is provided "as is" without warranty of any kind. Results are for educational and utility purposes.