What does 99.9% uptime actually allow?
Pick an uptime target and see exactly how much downtime it permits — per day, week, month, and year — then track how fast a real month burns your error budget. Computed entirely on your device.
Error budget this month
Uptime targets and the downtime they allow
An uptime SLA is a promise about how little downtime you'll have over a period. The arithmetic is simple — allowed downtime = (1 − uptime) × length of the period — but the results surprise people because the percentages sound airtight and the minutes are brutal. Three nines (99.9%) sounds bulletproof; it's under 44 minutes a month. Four nines leaves you about 4 minutes. Five nines is 26 seconds.
Error budgets: the number that actually runs your reliability
The gap between your target and 100% is your error budget — the downtime you're allowed to "spend" before you breach. Every outage, maintenance window, and bad deploy draws it down. The error-budget tracker above shows how fast a single incident eats a month: at 99.9%, one 30-minute bad deploy spends two-thirds of your entire monthly allowance in one afternoon.
Changes are an important, controllable source of downtime: deploys, migrations, configuration edits, and automation acting on production. A repeatable release and recovery workflow helps reduce that risk without pretending it disappears.
Spend your budget on real surprises, not avoidable mistakes
Manage releases as an operating sequence: check the new service, control the cutover, watch health, and prepare recovery. Infraveil carries out that workflow for managed backend services on your servers. Choose manual review for risky releases, or allowlist and automatic approval where your policy permits them; plan database recovery separately.
Stop spending nines on self-inflicted outages.
Infraveil manages software on servers you control. Choose manual, allowlist, or automatic approval for managed changes, then use the dashboard to see health, change history, and the recovery controls available for each service.
See the live demo →Frequently asked questions
How much downtime does 99.9% uptime allow?
About 43.8 minutes per month, ~10 minutes per week, ~1.4 minutes per day, and ~8h 46m per year. That allowance is your error budget.
What's the difference between 99.9% and 99.99%?
An order of magnitude: 99.9% allows ~44 min/month, 99.99% allows ~4 min/month. Each extra nine cuts your allowed downtime by 10×, and usually costs far more than 10× the engineering to achieve.
What is an error budget?
The amount of downtime your SLA permits before you're in breach. Track it like a balance: outages and risky deploys are withdrawals.
How do I stop deploys from burning my budget?
Use manual approval for high-risk changes, limit access, and plan recovery before release. For lower-risk work, an allowlist or automatic approval may fit your policy. See the Infraveil workflow →