--- title: "What is uptime and what does a 99.9 percent SLA mean | StreetHosting" description: "Understand uptime, SLA and how much downtime per year each level allows. Learn to read 99.9 and 99.99 percent promises and what to demand from a host." url: "https://streethosting.com.br/en/guides/infrastructure/what-is-uptime-and-sla" type: "page" language: "en-US" --- Infrastructure · 3 min · Beginner Published on Jun 17, 2026 · Updated on Jun 17, 2026 # Uptime and SLA: what 99.9 percent means Every provider promises high availability, but few explain what that means in hours. Here is the math behind uptime and what a real SLA should guarantee. By [Equipe StreetHosting](https://streethosting.com.br/en/autores#equipe-streethosting) · StreetHosting infrastructure and support team [Monitoring and alerts](https://streethosting.com.br/en/guides/topics/monitoring) Summarize with: [](https://chat.openai.com/?q=Summarize%20the%20key%20points%20of%20this%20StreetHosting%20guide%3A%20https%3A%2F%2Fstreethosting.com.br%2Fen%2Fguides%2Finfrastructure%2Fwhat-is-uptime-and-sla.%20Highlight%20the%20step-by-step%20instructions%2C%20the%20prerequisites%20and%20the%20most%20common%20mistakes. "ChatGPT") [](https://claude.ai/new?q=Summarize%20the%20key%20points%20of%20this%20StreetHosting%20guide%3A%20https%3A%2F%2Fstreethosting.com.br%2Fen%2Fguides%2Finfrastructure%2Fwhat-is-uptime-and-sla.%20Highlight%20the%20step-by-step%20instructions%2C%20the%20prerequisites%20and%20the%20most%20common%20mistakes. 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"Perplexity") Share: [](https://x.com/intent/tweet?text=What%20is%20uptime%20and%20what%20does%20a%2099.9%20percent%20SLA%20mean&url=https%3A%2F%2Fstreethosting.com.br%2Fen%2Fguides%2Finfrastructure%2Fwhat-is-uptime-and-sla "Share on X") [](https://www.facebook.com/sharer/sharer.php?u=https%3A%2F%2Fstreethosting.com.br%2Fen%2Fguides%2Finfrastructure%2Fwhat-is-uptime-and-sla "Share on Facebook") [](https://www.linkedin.com/sharing/share-offsite/?url=https%3A%2F%2Fstreethosting.com.br%2Fen%2Fguides%2Finfrastructure%2Fwhat-is-uptime-and-sla "Share on LinkedIn") [](https://wa.me/?text=What%20is%20uptime%20and%20what%20does%20a%2099.9%20percent%20SLA%20mean%20https%3A%2F%2Fstreethosting.com.br%2Fen%2Fguides%2Finfrastructure%2Fwhat-is-uptime-and-sla "Share on WhatsApp") For agents: Copy as Markdown [.md](https://streethosting.com.br/en/guides/infrastructure/what-is-uptime-and-sla.md) In this guide 5 sections * [What uptime is](https://streethosting.com.br/en/guides/infrastructure/what-is-uptime-and-sla#o-que-e-uptime) * [The SLA math](https://streethosting.com.br/en/guides/infrastructure/what-is-uptime-and-sla#a-conta-do-sla) * [Reading the promises](https://streethosting.com.br/en/guides/infrastructure/what-is-uptime-and-sla#ler-promessas) * [What to demand](https://streethosting.com.br/en/guides/infrastructure/what-is-uptime-and-sla#o-que-cobrar) * [In practice](https://streethosting.com.br/en/guides/infrastructure/what-is-uptime-and-sla#na-pratica) Quick answer **Uptime** is the time your service stays available. A **99.9 percent SLA** allows about eight to nine hours of downtime per year. Each extra nine shrinks that limit a lot. Beyond the percentage, what counts is how the provider responds to incidents. Check the real uptime with external monitoring. ## What uptime is[](https://streethosting.com.br/en/guides/infrastructure/what-is-uptime-and-sla#o-que-e-uptime) Uptime is the fraction of time your service was online. The opposite is downtime, the time it was offline. Providers express this commitment as an SLA, an availability percentage. Understanding the math behind it helps you tell marketing from a real guarantee, which is essential when evaluating [what to ask for in a support SLA](https://streethosting.com.br/en/guides/infrastructure/game-hosting-sla). ## The SLA math[](https://streethosting.com.br/en/guides/infrastructure/what-is-uptime-and-sla#a-conta-do-sla) | SLA | Maximum downtime per year (approximate) | | -------------- | --------------------------------------- | | 99 percent | More than three days | | 99.9 percent | About eight to nine hours | | 99.99 percent | Less than one hour | | 99.999 percent | A few minutes | ## Reading the promises[](https://streethosting.com.br/en/guides/infrastructure/what-is-uptime-and-sla#ler-promessas) A high percentage is good, but it does not tell the whole story. Eight hours of downtime spread across announced maintenance windows hurt less than eight hours in the middle of peak time, with no warning. Ask when maintenance happens and how the provider communicates incidents. A serious provider publishes a status page. See how to build yours in [creating an incident status page](https://streethosting.com.br/en/guides/infrastructure/incident-status-page). ## What to demand[](https://streethosting.com.br/en/guides/infrastructure/what-is-uptime-and-sla#o-que-cobrar) * A clear SLA percentage, in writing * A maintenance policy announced in advance * A channel for incident communication * Defined compensation if the limit is exceeded ## In practice[](https://streethosting.com.br/en/guides/infrastructure/what-is-uptime-and-sla#na-pratica) The best way to build trust is to measure it yourself. Set up external monitoring by following [monitoring with Uptime Kuma](https://streethosting.com.br/en/guides/vps/uptime-kuma-vps-monitoring). For projects that need maximum availability, explore [dedicated servers](https://streethosting.com.br/en/dedicated) and [Ryzen VPS](https://streethosting.com.br/en/vps/ryzen). In this guide * [What uptime is](https://streethosting.com.br/en/guides/infrastructure/what-is-uptime-and-sla#o-que-e-uptime) * [The SLA math](https://streethosting.com.br/en/guides/infrastructure/what-is-uptime-and-sla#a-conta-do-sla) * [Reading the promises](https://streethosting.com.br/en/guides/infrastructure/what-is-uptime-and-sla#ler-promessas) * [What to demand](https://streethosting.com.br/en/guides/infrastructure/what-is-uptime-and-sla#o-que-cobrar) * [In practice](https://streethosting.com.br/en/guides/infrastructure/what-is-uptime-and-sla#na-pratica) ## Frequently asked questions How many hours of downtime does a 99.9 percent SLA allow? About eight to nine hours per year. That may sound small, but concentrated during peak hours it makes a difference. So besides the percentage, what matters is when and how the provider responds to incidents. Are 99.9 and 99.99 percent very different? Yes. Each extra nine drastically cuts the allowed hours of downtime. From 99.9 to 99.99 percent, the limit drops from hours to less than one hour per year. The more nines, the more robust the infrastructure. Does an SLA guarantee it will never go down? No. It sets a commitment and, often, compensation if the limit is exceeded. No system is perfect. The value of an SLA lies in how clear the commitment is and how serious the operation behind it is. How do I check the real uptime? With external monitoring, outside the provider's network. Tools that check your service from the outside measure availability independently and show whether the promise is being kept. Next step See dedicated servers Exclusive hardware in São Paulo with NVMe and Anti-DDoS. [See dedicated servers](https://streethosting.com.br/en/dedicated) [See Ryzen VPS Ryzen 9 9950X VPS in São Paulo with root access, NVMe and gamer Anti-DDoS.](https://streethosting.com.br/en/vps/ryzen) [See Minecraft Pro Managed hosting on Ryzen with modpacks, optimized Paper and technical support.](https://streethosting.com.br/en/minecraft-pro) ## Related guides [Infrastructure Beginner SLA and support in game hosting: what to demand Support that only opens a generic ticket at 9 a.m. while your season is on fire at 10 p.m. is not cheap: it has a hidden cost. This guide lists what to ask for before you pay for a year. 2 min Read guide](https://streethosting.com.br/en/guides/infrastructure/game-hosting-sla) [Infrastructure Beginner How to create a status page for server incidents A status page cuts support noise and builds customer trust by showing incidents and updates in real time. 2 min Read guide](https://streethosting.com.br/en/guides/infrastructure/incident-status-page) [VPS Intermediate How to install Uptime Kuma on a VPS and monitor sites and ports Uptime Kuma checks sites, APIs, ports and scheduled jobs at set intervals and alerts you when something goes down. Here is how to install it with Docker, serve it over HTTPS, pick the right monitor type and turn on alerts. 8 min Read guide](https://streethosting.com.br/en/guides/vps/uptime-kuma-vps-monitoring) [← Back to the Guide Center](https://streethosting.com.br/en/guides)