How much downtime does 99.9999% uptime allow?
99.9999% (six nines) uptime allows 32s of downtime per year. Here is the full budget, by period.
| Per day | 0s |
| Per week | 1s |
| Per month | 3s |
| Per quarter | 8s |
| Per year | 32s |
Is 99.9999% (six nines) the right target?
Six nines is the realm of ultra-critical systems — carrier-grade switching, certain financial market infrastructure, and safety-critical control systems. The annual budget is about half a minute, so the architecture itself, not operations, has to absorb faults.
What it takes to hold 99.9999%
Fully redundant, self-healing systems with no single point of failure and automated, sub-second failover. At roughly 31 seconds per year this is a hardware and network engineering problem, not an ops one.
Where you’ll see 99.9999%
- Carrier-grade telephone switching
- Certain financial market infrastructure
- Safety-critical control systems
Each additional nine cuts the allowed downtime by roughly tenfold. The chart below shows where 99.9999% sits relative to the other common uptime targets — and why detection speed, not just the headline percentage, decides whether you actually hold the line.
Frequently asked questions
- How much downtime is 99.9999% uptime?
- 99.9999% uptime allows only about 31 seconds per year — a few seconds per month. At this level downtime is effectively a rounding error, achievable only with fault-tolerant hardware.
- Is six nines realistic for software?
- Almost never for application software. Six nines is an engineering property of fault-tolerant systems — redundant hardware, networks, and power — rather than something an ordinary deployment can promise.
- How do I monitor a service to 99.9999%?
- You need sub-second visibility just to measure it meaningfully. PingInsight's one-second checks and millisecond-stamped timelines are the floor for verifying a six-nines budget.
Compare every tier on the full uptime / SLA calculator, read what “three nines” really means, or see how 1-second uptime monitoring helps you stay inside this budget.
| Period | Allowed downtime |
|---|---|
| Per day | 0s |
| Per week | 1s |
| Per month | 3s |
| Per quarter | 8s |
| Per year | 32s |
Detection matters as much as the budget. With 5-minute monitoring you can burn minutes of this allowance before you even detect an outage. PingInsight's true 1-second checks catch it almost immediately.
Back to the full uptime calculator or see how 1-second checks help you stay within budget.