Uptime, downtime & what they mean

When people talk about hosting reliability, they talk about uptime: how often your website is available to visitors. When your site is unavailable, that's called downtime. Here's what these terms mean and why they matter.

Who keeps your site online

That depends on how your site is built. There are three common setups, and the answer is different for each:

A website platform such as Squarespace, Wix, Shopify or Webflow runs the servers and the software for you. When an outage starts on their side, they fix it. What's still yours: your domain, your subscription being paid, and anything you add yourself, like apps, embeds or custom code.
WordPress or another self-hosted site sits on server space you rent from a host, such as Kinsta, WP Engine, Flywheel or GoDaddy. The host keeps the server running. The software on it (WordPress, its plugins and theme) is yours or your developer's to keep working.
A custom-built site or web app usually runs on a cloud service such as Vercel, Netlify or a cloud provider. The service keeps its infrastructure up. The code is yours or your developer's.

Every setup can go down, and the checks below work for all three.

What uptime means

Uptime is expressed as a percentage of total time:

Uptime	Annual downtime
99%	~87.6 hours/year (~3.6 days)
99.9%	~8.76 hours/year
99.95%	~4.38 hours/year
99.99%	~52.6 minutes/year

99.9% uptime is a figure you'll often see quoted, but where a guarantee exists it usually comes with your plan rather than with the company in general. Among managed WordPress hosts, for example, Kinsta's documentation describes an uptime guarantee of up to 99.9%, and up to 99.99% on custom plans. WP Engine lists a 99.99% uptime SLA on its higher plans, not on its entry plan. If the guarantee matters to you, check your plan's terms, or ask us.

The difference between 99% and 99.9% is significant. 87 hours offline per year is nearly four full days: enough to cause real damage to a business.

To see what those hours could cost your business, enter your own figures below. For a year at 99.9% uptime, try 8.76 hours offline. The downtime cost calculator page explains how the estimate works.

Try your numbers

What would an outage cost you?

Online sales

Revenue the website takes directly. Leave blank if you don’t sell online.

Leads or enquiries

Form fills, calls and bookings that come through the site.

Value of one lead

Deal size times the share you win. A $5,000 job won 1 time in 5 is $1,000.

How long is the site offline?

Your estimate

Add your online sales or your leads, and the cost of an outage shows here.

Which of these sounds like your outage?

Downtime has a handful of usual causes. Tick anything that matches what happened to see which ones to read first.

Tick anything that sounds like your siteMy host or platform emailed me about maintenance, and the outage was in the middle of the night.My host's or platform's status page is reporting an incident.The site went down right when a lot more people than usual were visiting.I've had emails from my host or platform about a payment that didn't go through.My domain was due for renewal, or someone recently changed its DNS settings.The site shows a white screen or an error, right after an update, a new plugin or app, or a code change.

Nothing sounds familiar? Work through the checks one at a time: my website is down.

What causes downtime

Planned maintenance

Hosts occasionally take servers offline briefly for upgrades or maintenance. They schedule it for quiet hours (Kinsta's maintenance window is 2am to 5am in the time zone of the data center your site sits in) and email you in advance about bigger jobs. Kinsta says a site is usually offline for less than a minute during one of its infrastructure upgrades. This is the least disruptive type of downtime.

Server issues

Hardware failures, software bugs, or resource overloads on the hosting side. Hosts watch for this themselves: Kinsta says it monitors every site on its platform and that its engineers respond as soon as one of those checks fails.

Traffic spikes

An unexpected surge in visitors can overwhelm a server. Website platforms, managed hosts and CDNs are built to absorb sudden traffic far better than basic shared hosting.

Hosting account suspension

If a hosting account or website platform subscription is suspended over an unpaid invoice, the site stops serving visitors. Companies usually email you and retry the card first (on Kinsta that plays out over about two weeks) so this is usually avoidable. Keep the card on file current, wherever your site lives. See renewing hosting & avoiding lapses.

DNS or domain issues

If your domain expires or DNS records are changed incorrectly, your site becomes unreachable even though the server is running fine. See how DNS & hosting fit together.

Plugin, app or code errors

A bad update or a coding mistake can take a site down, or leave a white screen or an error page where it used to be. What that looks like depends on the setup:

WordPress: a plugin or theme update. See My WordPress site is down and fixing the "white screen" error.
Website platforms: an app, an embed or custom code you added. On Shopify, Squarespace and Webflow, start with troubleshooting Shopify, troubleshooting Squarespace or troubleshooting Webflow.
Custom-built sites: a release that went out with a bug in it. Your developer can usually roll it back to the last working version.

This isn't technically a hosting issue, but visitors still see a broken site.

DDoS attacks

A distributed denial-of-service attack floods your server with fake traffic. Website platforms, managed hosts and CDNs have protections against this: CDNs and firewalls absorb most attacks.

How to check if your site is down

Try your site in a different browser or an incognito/private window. Sometimes browser cache creates the appearance of a problem that isn't real.

Ask someone else to try: on a different network (e.g. their phone data). If they can see it and you can't, the issue may be specific to your device or network.

Use a free online "is it down?" checker, such as Is It Down Right Now?, to confirm the site is unreachable for everyone, not just for you.

Check your host's or platform's status page. If they're having an outage, it shows up here first.

Website platforms: Squarespace, Shopify, Wix, Webflow
WordPress hosts: Flywheel, WP Engine, Kinsta
Other hosts and services: GoDaddy, Cloudflare (if your domain or CDN runs through it), Vercel, Netlify

Not listed? Search for "[your host or platform] status".

What to do when your site is down

Check the status page (links above). If your host or platform is reporting an incident, all you can do is wait. They're already working on it.

Contact your host's or platform's support if there's no active incident reported but your site is down. Provide your site URL and a description of what you're seeing.

Contact us if the issue isn't resolved quickly or if you need help diagnosing the cause.

Uptime monitoring

We include uptime monitoring for sites on our care plans. If your site goes down, we're alerted immediately, often before you notice. We'll investigate and resolve the issue, and notify you if anything requires action on your part.

Common questions

My site was down briefly but is back now: should I be worried?

Brief, infrequent outages are normal. If it happens regularly or for extended periods, it's worth investigating. Contact us and we'll review the hosting logs.

Does downtime affect my Google ranking?

A brief outage is unlikely to hurt your SEO. Google says server errors make its crawler slow down, and that pages already in the index are kept there at first. Pages that keep returning a server error are eventually dropped from the index, so it's a long outage (or the same one happening over and over) that does the damage.

What is a 99.9% uptime SLA?

SLA stands for Service Level Agreement: a commitment from your host or platform to maintain a certain uptime level. If they fall below it, you may be entitled to a credit on your hosting fee. Check your plan's terms.