SLO & Error Budget Calculator
Calculate SLO error budgets and track consumption for reliability management. Enter values for instant results with step-by-step formulas.
Worked Examples
Example 1: Three Nines SLO - Healthy
Problem:99.9% SLO over 30 days. Actual uptime: 99.92%. Error budget: 43.2 minutes. Consumed: 34.6 minutes. 2 incidents.
Solution:Meeting SLO with 8.6 minutes (20%) budget remaining. Healthy state—can continue normal deployment velocity.
Result:99.92% uptime | 20% budget left | 8.6 min remaining | Continue normal operations
Example 2: Error Budget Exhausted
Problem:99.9% SLO. Actual: 99.82%. Budget: 43.2 min. Consumed: 77.8 min. 5 incidents totaling 80 minutes downtime.
Solution:SLO breach. Error budget exhausted 180%. Freeze risky changes. Focus on stability. Root cause analysis required for all 5 incidents.
Result:99.82% uptime | SLO MISS | Budget 180% over | Code freeze protocol
Example 3: Four Nines - Aggressive SLO
Problem:99.99% SLO (4.32 minutes/month budget). Actual: 99.985%. 1 incident = 6.5 minutes downtime.
Solution:Missed SLO despite good uptime—the SLO is very aggressive. Budget exceeded 150%. Review if 99.99% is necessary or if 99.95% would suffice.
Result:99.985% uptime | Missed 99.99% SLO | Consider relaxing SLO target
Frequently Asked Questions
What is an SLO (Service Level Objective)?
An SLO is a target level of service you promise to users, typically expressed as a percentage (e.g., 99.9% uptime). It's the threshold between acceptable and unacceptable service quality, set by balancing customer needs against engineering constraints.
What is an error budget?
Error budget is the allowed amount of downtime or errors within your SLO. If your SLO is 99.9% uptime, your error budget is 0.1% downtime (43.2 minutes/month). It quantifies how much you can 'spend' on risk (deployments, changes) vs. focusing on stability.
What's a good SLO target?
It depends on user needs and service criticality. Consumer apps: 99-99.5%. Business apps: 99.5-99.9%. Critical infrastructure: 99.95-99.99%. Higher SLOs cost exponentially more. Don't target perfection (99.999%) unless absolutely necessary.
How do you calculate error budget?
Error Budget = Total Time × (100% - SLO Target). For 30 days at 99.9% SLO: 43,200 minutes × 0.1% = 43.2 minutes allowed downtime. Track consumed vs. remaining budget to manage deployment risk.