Uptime

Uptime sounds binary but is not. A site can respond to a monitoring check with a normal status code while its contact form fails, its checkout errors or it loads so slowly that visitors leave. A page that answers is "up" to a simple monitor; whether it works for customers is a separate question.

Hosting providers often promise a level of uptime in a service level agreement (SLA). That promise usually only covers their infrastructure, excludes planned maintenance and offers service credits rather than compensation for lost business. Read how the agreement defines downtime, since some count only complete outages lasting longer than a set number of minutes.

How it works

The numbers are simple arithmetic. A month of 30 days has 43,200 minutes, so 99.9% uptime allows about 43 minutes of downtime that month, or roughly 8 hours 46 minutes over a year. 99.99% allows about 4 minutes a month, or around 53 minutes a year. Each extra nine is ten times stricter and usually much more expensive to deliver.

Uptime monitors measure it from outside. A monitoring service requests a page every few minutes from several locations and records whether it answers correctly and how long it takes. If checks fail from more than one location, it alerts you by email, text or an app, and later reports the total downtime. Better monitors also check that the page contains an expected word, so an error page served with a normal status code still counts as down.

Downtime has different causes, and the fix depends on which one it is: the server or host failing, DNS problems, an expired certificate, a broken update, traffic beyond what the plan allows or an attack such as a DDoS. A monitor tells you that something is down; logs and the host's status page help tell you why.

Example

A wedding venue's site goes down on a Saturday evening after an automatic plugin update conflicts with the theme. Without monitoring, nobody notices until Monday, by which time several enquiries have been lost to a white screen. With a free uptime monitor set to check the contact page for the word "Enquire", the owner gets a text within minutes, and the developer rolls back the update from a backup that night.

Over the following months the monitor's report shows two other short outages, both during the host's maintenance windows. That record is useful evidence when the venue later compares hosting providers.

Why it matters for your business

Downtime costs leads, sales and trust, and repeated outages can affect how search engines crawl a site. Most small businesses do not need extreme uptime targets; they need to know quickly when the site is down and have someone ready to fix it. Free and low-cost monitoring covers that. Paying for higher uptime guarantees makes sense when the site itself takes money around the clock, such as a busy shop or booking system, and even then, recovery speed matters as much as the percentage on the contract. Whatever you choose, write down who receives the alert and what they do first, so a weekend outage does not wait until Monday.

Common mistakes

• Trusting the host's uptime figure without running your own independent monitoring.
• Monitoring only the home page while the contact form or checkout is what actually breaks.
• Sending downtime alerts to an address nobody reads at weekends.
• Treating an SLA credit as protection, when it rarely covers the business lost during an outage.

Questions people ask

What is a good uptime percentage for a website?

Most reputable hosts aim for 99.9% or higher, which allows about 43 minutes of downtime in a 30-day month. For a small business site that is usually acceptable. What matters more is how quickly you learn about an outage and how fast it is fixed.

How can I check my website's uptime?

Set up an uptime monitoring service, many of which have free plans, to check your key pages every few minutes from several locations. It will alert you when the site stops responding and keep a history of outages you can compare against your host's claims.

Why is my website down but working for me?

You may be seeing a cached copy, a different server through a CDN or an old DNS answer. Try a different network, such as mobile data, or an online checking tool that tests from several locations. If it fails elsewhere, contact your host with the times and error messages.