What uptime numbers really mean
99.9% sounds reassuring. Here's what it translates to in downtime per year, and which providers consistently exceed it.
Every host advertises 99.9% uptime. Almost none of them define what that actually means for your business.
The math
99% uptime = 3.65 days of downtime per year.
99.9% uptime = 8.76 hours per year.
99.99% uptime = 52.6 minutes per year.
99.999% uptime = 5.26 minutes per year.
The difference between 99.9% and 99.99% is an order of magnitude.
Who actually delivers
In our long-term monitoring, WPX and Hostwinds routinely measure above 99.99%. DreamHost backs a 100% uptime SLA with credits if it slips. Mainstream shared hosts cluster around 99.9% in practice, which is fine for most use cases but worth knowing.
When uptime matters most
For revenue-generating sites — e-commerce, lead capture, SaaS — every hour of downtime has a real cost. For a personal blog, the difference between 99.9% and 99.99% is mostly philosophical.
Questions readers ask about this topic
What does 99.9% uptime actually mean?
Are uptime guarantees worth anything?
Do I need third-party monitoring?
Where to go next on Hostilo
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