What Is Website Downtime?

Category: Hosting Basics · Updated 2026-10-30

Website downtime is any period during which a site cannot be reached or does not work properly for visitors, whether caused by the hosting server, the network, DNS or the site's own code. Downtime is split into planned downtime, announced in advance for maintenance, and unplanned downtime, caused by an unexpected failure.

Planned vs. unplanned downtime

	Planned downtime	Unplanned downtime
Cause	Scheduled maintenance, upgrades, migrations	Server crash, network failure, attack, bad deployment
Warning	Usually announced in advance	No warning
Counted against SLA	Often excluded if properly announced	Usually counted
Typical length	Minutes, timed for low-traffic hours	Minutes to hours, depending on the cause

Common causes of downtime

Hosting server issues: hardware failure, resource limits reached, or the host's own outage.
Site-side errors: a broken plugin, theme update, or misconfigured code that crashes the application.
DNS problems: an expired domain, a misconfigured DNS record, or a nameserver outage, which can take a site offline even if the server itself is healthy.
Traffic spikes: a sudden surge that exceeds the plan's capacity, common after a viral post or a marketing campaign.
Security incidents: malware infections or a denial-of-service attack overwhelming the server.
SSL certificate expiration: browsers can block access entirely once a certificate lapses.

The real cost of downtime

The exact cost of an outage varies enormously by site and cannot be stated as a single number, but the categories of impact are predictable: lost sales during the outage window for a store, lost leads for a business site, support tickets and refund requests, and a search engine that may crawl the site less favorably if outages happen often or during a crawl attempt. For most sites, the business impact of downtime grows roughly with how long it lasts and how central the site is to daily operations.

Reducing the risk of downtime

Choose a host with a track record of reliability and a clear uptime guarantee.
Keep software, themes and plugins updated, and test major updates on a staging site first.
Set up uptime monitoring so you learn about problems in minutes, not from a customer complaint.
Keep regular backups so a bad change can be rolled back quickly.
Renew the domain and SSL certificate well before they expire, ideally with auto-renewal enabled.
Use a CDN or caching to absorb traffic spikes before they reach the origin server.

Frequently asked questions

What causes most website downtime?

Common causes include hosting server problems, a broken plugin or bad code deployment, DNS misconfiguration, an expired SSL certificate or domain, and traffic spikes that exceed the plan's capacity.

What is the difference between planned and unplanned downtime?

Planned downtime is scheduled maintenance announced in advance, usually timed for low-traffic hours, while unplanned downtime is an unexpected failure with no warning. Hosting SLAs often exclude properly announced planned downtime from their uptime calculation.

How do I know if my website is down right now?

Check the site from a different network or device, since local internet problems can look like a site outage, and use an uptime monitoring tool or a free "is it down" checker to confirm from outside your own connection.

Can DNS issues cause downtime even if the server is fine?

Yes. If a domain's DNS records are misconfigured, the nameservers are unreachable, or the domain expires, visitors cannot reach the site at all even though the hosting server is running normally.

How quickly should downtime be fixed?

As quickly as the cause allows. Simple issues like a bad plugin or a misconfigured redirect can often be reversed within minutes, while hardware failures or DNS propagation delays can take longer, which is why monitoring and backups matter for cutting response time.

Does downtime hurt SEO?

Occasional short outages have little lasting effect. Frequent or long outages, especially if a search engine's crawler repeatedly hits a down site, can reduce crawling and may affect rankings over time.