How to Check Website Speed on a Phone and Fix It

Your boss texts you a link. You tap it. The page stays white. You go back and pick the next option.

To check website speed, open your page in Google's PageSpeed Insights, then open it yourself on a phone using mobile data. Three seconds is the line to beat. Google's analysis found that 53% of mobile site visitors leave a page that takes longer than three seconds to load.

How fast is fast enough on a phone?

Under three seconds. After that, more than half of mobile visitors in Google's data were gone.

That 53% comes from Google Analytics data on 3,700 mobile sites, gathered in March 2016 and published in February 2017. The same report used a model trained on bounce and conversion data. It estimated that as load time goes from 1 second to 7 seconds, the chance a mobile visitor bounces rises 113%.

Treat these as direction, not law. The data is nearly a decade old. The load-time tests ran on an emulated 3G connection, which is slower than most phones get today. Your buyers on 5G or office Wi-Fi will see faster pages.

What does a slow page cost a lead-gen site?

Deloitte and Google's "Milliseconds Make Millions" tracked 37 brand sites and over 30 million user sessions for 30 days at the end of 2019. On lead-generation sites, a 0.1-second speed improvement went with up to a 21.6% rise in users reaching the form page.

Read "up to" literally. It's the biggest effect the study found. And every page in the journey had to get 0.1 seconds faster on each of four speed metrics. One of them, First Meaningful Paint, is now deprecated, and the article recommends Largest Contentful Paint instead.

Portent's analysis covers about 100 million page views across 20 sites, 14 of them B2B lead generation. It found that a B2B site loading in 1 second converts 3 times better than one loading in 5. Portent is a marketing agency, and its data is not independent.

Neither study measures your site. They show the shape of the problem.

How do you check website speed for free?

Use your own phone. A desktop test on office Wi-Fi flatters you.

1. Open PageSpeed Insights and paste your homepage address. Read the mobile result first.
2. Run it three times. Lab scores move a little from run to run. Look at the pattern.
3. Open the page on your phone with Wi-Fi off. Count to three. Did the first screen appear?
4. Ask a coworker to try theirs. Their phone and their signal are not yours.
5. Run the Swift Site Audit. Its Open step pulls speed from Google PageSpeed and reads the first screen and accessibility on the same visit.

Our own phone speed score is 64, and we haven't fixed it yet. We'd rather say so than hide it.

How do you read the result?

Look at the mobile tab, not the desktop one. Then look at Largest Contentful Paint, which is the time until the biggest thing on the first screen appears. That's the moment your buyer sees something worth waiting for.

A single score hides the cause. The report also lists what slowed the page, and the biggest items sit at the top. Start there.

Lab and field data differ too. A lab test is one run on one setup. Real visitors have older phones, weaker signals and busy browsers. If PageSpeed shows field data for your site, trust it over the lab number.

What usually makes a page slow, and what do you fix first?

Big things first. Oversized images and extra scripts such as chat widgets and trackers are the usual suspects. Chrome DevTools and WebPageTest both show which files weigh the most.

Google's 2017 analysis points the same direction. As the number of elements on a page went from 400 to 6,000, the model estimated the chance of a conversion dropped 95%. For 70% of the pages Google tested, the visual content above the fold took nearly seven seconds to appear on its emulated 3G test.

Work in this order:

1. Shrink or remove the heaviest image.
2. Remove a script nobody uses.
3. Test again.
4. Move to the next heaviest file.

A fast lab score can still hide a slow page for people on weak signals. And speed is one step of the visit. A fast page that says nothing clear on its first screen still loses the buyer.

What if your site runs on WordPress, Squarespace or Shopify?

You can still fix most of it. Resize the images before you upload them. Remove apps and plugins you no longer use. Each one adds code to every page.

The theme and the host set a floor, though. If a heavy theme loads on every page, no image trick will beat it. In that case, ask your developer or your site builder's support what a lighter theme would cost, and test the change on one page first.

Keep one fact in mind while you work. The buyer doesn't care why the page is slow. They only feel that it is.

How do you compare before and after?

Keep a small log. Without one, a score you felt good about last month is just a feeling.

Date	Page	Mobile score	What changed
Today	Homepage	Write it here	Nothing yet
After fix 1	Homepage	Write it here	Shrank the largest image

Test the same page, on the same phone, at about the same time of day. Change one thing between runs. If the score drops after a change, you've learned the change hurt, which is also useful.

Our own phone speed score is 64. We haven't fixed it yet, and the log is how we'll know when we do.

Is a desktop score enough?

No. A desktop test runs on a fast machine with a wired or office connection, so it flatters almost every site. Buyers who open your link from a text message are on a phone, often on a mobile signal.

Read the mobile result first. If your desktop score is good and your mobile score is poor, believe the mobile one. It is the one most of your buyers meet.

FAQ

What is a good website speed on mobile?

Aim for a page that shows its first screen in under three seconds on a phone. Google's data found that 53% of mobile visitors leave after that.

Why does my speed score change between runs?

Lab tests vary a little each time. Run the test three times and look at the middle result.

Can the Swift Site Audit fix my speed?

No. It measures speed and tells you where you lose points. Fixing the files is the next step.

Say your page opens fast. Next, your buyer reads the first screen. If you want a person to look at your speed, book a free 30-minute consultation. We want your success as much as you do.