What uptime really means, how much downtime 99.9% allows, what to monitor beyond 'is it up', free and paid monitoring options, alerts and status pages, and what to do when your site goes down.
If your website goes down, you might not notice until a customer tells you. Uptime monitoring checks your site automatically and alerts you when something breaks. It's cheap or free, and quick to set up.
What uptime percentages mean?
Hosts often advertise uptime guarantees. Here's roughly how much downtime each allows:
| Uptime | Per month (about) | Per year (about) |
|---|---|---|
| 99% | 7 hours 18 minutes | 3.65 days |
| 99.5% | 3 hours 39 minutes | 43.8 hours |
| 99.9% | 44 minutes | 8.8 hours |
| 99.99% | 4.4 minutes | 53 minutes |
Read the service level agreement (SLA) carefully. Many exclude scheduled maintenance, and compensation is usually a small credit, not payment for lost business.
What to monitor?
- HTTP checks: does the page return a successful status code?
- Keyword checks: does the page contain expected text? A site can return a "success" code while showing an error message or a blank page.
- Key journeys: for shops, check the basket or checkout page, not just the homepage.
- SSL certificate expiry: an expired certificate shows visitors a security warning.
- Domain expiry: a lapsed domain takes everything offline, including email.
- Response time: slow pages can be an early warning of problems.
- DNS: checks that your domain resolves correctly.
How often to check?
Free plans commonly check every five minutes, which suits most small sites. Paid plans offer one-minute or more frequent checks and testing from several locations, which reduces false alarms caused by a single network problem.
Monitoring options
- Free external monitoring services: many offer free tiers that cover a handful of sites with email or app alerts.
- Your host or CDN: some include basic health checks or analytics.
- Self-hosted tools: open-source monitors you run yourself, useful if you're technical, but they need to run somewhere other than the site they're watching.
Whatever you choose, monitoring should run from outside your hosting, so it still works when your server is down.
Set up alerts that work
- Send alerts to at least two people or channels, such as email and a phone app.
- Require a failure from more than one location, or two checks in a row, before alerting, to cut false alarms.
- Test alerts by pausing a page or pointing a test monitor at a non-existent URL.
Planned maintenance
If you need to take the site offline on purpose, show a maintenance page that returns an HTTP 503 status ("service unavailable") rather than a normal page. Google's guidance says this tells search engines the outage is temporary. Leaving a site returning errors or a blank page for days risks pages dropping out of search results. Pause your monitors during the work so you don't get flooded with alerts.
Status pages
A public status page lets customers see whether there's a known problem and when it was fixed. Many monitoring services can create one automatically.
When your site goes down?
- Confirm: check from another device or network, or use an online "is it down" checker.
- Check the host's status page for known incidents.
- Check renewals: domain, hosting and certificate.
- Check recent changes: updates, plugins, DNS edits or deployments are common causes. Roll back if needed.
- Contact support with times, error messages and screenshots.
- Communicate: update customers through your status page or social media.
- Review afterwards: note the cause and what would prevent it.
Frequently asked questions
Is 99.9% uptime good?
It's a common standard for small business hosting. Critical services aim higher, at greater cost.
Can monitoring slow my site?
No. A check every few minutes is a negligible load.
Sources and further reading
Facts checked on 20 October 2026. Spotted an error? Tell us and we will correct it.