Uptime
Quick Definition
Uptime is the percentage of time your website is online and accessible to visitors. Hosting providers typically guarantee 99.9% uptime, which still allows for about 8 hours and 46 minutes of downtime per year.
What Is Uptime?
Uptime is the amount of time your website is online, working, and accessible to visitors. It is usually expressed as a percentage over a given period — typically a month or a year. The opposite of uptime is downtime: the time your site is unavailable due to server issues, maintenance, cyberattacks, hardware failures, or software problems.
When a hosting provider advertises "99.9% uptime," they are saying your site should be online 99.9% of the time. That sounds nearly perfect, but that 0.1% adds up:
| Uptime % | Downtime per month | Downtime per year |
|---|---|---|
| 99.0% | ~7 hours 18 min | ~3 days 15 hours |
| 99.9% | ~43 min 50 sec | ~8 hours 46 min |
| 99.99% | ~4 min 23 sec | ~52 min 36 sec |
| 99.999% | ~26 seconds | ~5 min 15 sec |
The industry standard for shared hosting and managed WordPress hosting is 99.9% (often called "three nines"). Premium hosts like Kinsta and WP Engine guarantee 99.9% or higher in their Service Level Agreement (SLA).
Uptime in Practice
An SLA is a contractual commitment from your host. If they fail to meet the guaranteed uptime percentage, you are typically entitled to account credits or a partial refund. However, there are important caveats:
- Scheduled maintenance is usually excluded from uptime calculations.
- Issues caused by your site — like plugin conflicts, database crashes, or bad code — are your responsibility, not the host's.
- Force majeure events (natural disasters, widespread internet outages) are excluded.
- Compensation is limited — usually just hosting credits, not reimbursement for lost revenue.
To monitor your own uptime, you can use free tools like UptimeRobot (checks every 5 minutes, sends alerts via email or Slack) or Better Uptime. These tools ping your site regularly and notify you immediately if it goes down — often before your host even knows.
Why It Matters
Every minute your site is down, you lose visitors, potential customers, and search engine trust. Google notices downtime: if your site is frequently unavailable, it can hurt your rankings. For an e-commerce store or business site, even 30 minutes of downtime during peak hours can mean significant lost revenue. Choosing a host with a strong uptime track record — not just a written guarantee — is one of the most important hosting decisions you will make.