Error budget & SLO calculator
Translate raw error rates into SLO numbers, error budgets, burn rate, and 9s of availability — for engineering managers who have to report up.
Free error budget calculator and SLO availability calculator for engineering managers. Enter your total requests, failed requests, and target SLO — get the error budget remaining, current burn rate, projected end-of-period success rate, and the equivalent 9s of downtime. Useful for status updates, post-incident reviews, and translating raw error counts into the language leadership uses.
If this rate continues, you'll end the period at 99.8400% (16,000 errors), which is below your 99.9% target.
Show the 9s table
Equivalent continuous downtime allowed at each SLO across your current 30-day period. (Most outages aren't continuous — this is the worst-case "all your budget at once" view.)
| Target SLO | Downtime / 30d | Per day |
|---|---|---|
| 99% | 7.20h | 14.4m |
| 99.5% | 3.60h | 7.20m |
| 99.9%current | 43.2m | 1.44m |
| 99.95% | 21.6m | 43.2s |
| 99.99% | 4.32m | 8.6s |
Show formulas
allowed_errors = total_requests × (1 − target_slo / 100) errors_used = failed_requests errors_remaining = allowed_errors − errors_used burn_rate = (errors_used / days_elapsed) ÷ (allowed_errors / period_length) projected_failed = errors_used × (period_length / days_elapsed) downtime_budget = period_length × (1 − target_slo / 100)
Burn rate is a multiplier of the sustainable rate: 1× means you'll exactly exhaust the budget at the end of the period, 2× means you'll burn through it in half the time. Anything above ~2× over a multi-hour window is typically the threshold for a page in Google's SRE workbook.
Inputs and calculations stay in your browser — nothing is sent to a server. Share the URL to share your scenario.
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