What is Uptime in Web Hosting?
Last updated: 10 December 2025
What is Uptime in Web Hosting?
Uptime is the time that a server is online and accessible. It is expressed as a percentage and indicates how reliable a hosting provider is. The higher the uptime, the less often your website is unreachable.
Uptime percentages explained
| Uptime % | Downtime per year | Downtime per month |
|---|---|---|
| 99.0% | 3.65 days | 7.31 hours |
| 99.9% | 8.77 hours | 43.83 min |
| 99.99% | 52.60 min | 4.38 min |
| 99.999% | 5.26 min | 26.30 sec |
Why is uptime important?
- Visitor experience - Unreachable websites frustrate visitors
- Revenue - Every minute of downtime costs potential sales
- SEO - A lot of downtime can negatively affect your rankings
- Trust - A stable website radiates professionalism
SLA and Uptime Guarantees
An SLA (Service Level Agreement) is an agreement between you and the hosting provider in which guarantees are recorded. Many providers offer:
- 99.9% uptime guarantee - Standard with most providers
- Compensation for downtime - Discount or credit for longer outages
- Excluded maintenance - Scheduled maintenance often does not count
Factors that affect uptime
- Server hardware - Quality and redundancy of hardware
- Datacenter - Location, cooling, power supply
- Network - Connections and DDoS protection
- Software maintenance - Updates and patches
- Traffic spikes - Overload due to many visitors
How do you check uptime?
There are various tools to monitor uptime:
- UptimeRobot (free)
- Pingdom
- StatusCake
- Better Uptime
These tools regularly check if your website is accessible and send alerts during downtime.
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