As Google continues its quest to “make the web more mobile-friendly,” businesses with websites built only for desktop computer viewing are at risk of slipping in search rankings. In 2014 Google started using websites’ mobile performance in the algorithms that determine where a site places in search rankings. Websites that look just as good on smartphones as they do on desktop computers actually get a boost in search rankings.

Beginning this May, Google will further improve the rankings that mobile-friendly sites receive in search results. This has small business owners hustling to make their sites better for smartphone and tablet users.

“One of our clients was actually not showing up in search results for mobile queries, due to a lack of a mobile version of their site,” said Garrett Smith, founder of Pitch + Pivot, a sales and marketing company based in Buffalo, New York.

Smith’s client was a doctor running a small practice with little time to keep up with Google’s algorithm changes. Still, the sudden drop in Google search ranking threatened the ability of the small medical office to attract new patients.

After building a more modern site—one made for use on smartphones as well as traditional computers—Smith said “the physician saw an increase in traffic of about 25%, total, which is over 100% more mobile traffic than they had.”

This is a common problem for small businesses, independent medical practices and small professional-service companies, according to Smith.

Dr. Alan J. Parks, founder and medical director of Eastside Dermatology & Skin Care Center in Columbus, Ohio, said his dermatology practice has seen a 55% increase in mobile website traffic since last year and more than 90% more traffic from two years ago.

Parks prides himself on keeping his small business on the cutting edge when it comes to digital marketing.  “We were one of the early adapters of a mobile-friendly site in our market, so this has been beneficial for website traffic,” he said. “Google seemed to have liked the modifications we made.”

As part of their website updates, Eastside Dermatology added a click-to-call button in a prominent position on their mobile site. Parks said this small improvement has helped convert web visitors into real-world customers.

“Additionally, it is easy to book an appointment online, as our patients have the capability to do this from desktop or mobile,” Parks said.

Regardless of the type of small business you operate, mobile is where you want to be. Google’s changes were prompted by a steep rise in consumer use of smartphones and tablets to search the Internet: up from 36% to 61% in the past two years alone.

Todd Damon has owned and operated Wood Werks Supply with his father, Ron, for 25 years. The woodworking equipment supplier sells much of its equipment through its ecommerce site.

“Google’s mobile rankings mean that each one of our product pages has to be optimized for mobile users. Fortunately, we developed our website with the mobile user in mind,” said Damon. “Rather than worrying about Google’s mobile rankings, we analyze the data to make sure our mobile user is having the best possible experience.”

This has increased the company’s rank in both desktop and mobile web searches for woodworking supplies. As a result, Wood Werks has seen a higher percentage of sales conversions over the past year from mobile website visitors.

“When the mobile user stays on your site for a long time and makes transactions, Google is going to like this activity,” said Damon. And small business owners like the additional sales activity generated from that increased mobile traffic.

Not sure if your website is mobile-friendly? You can start by running it through Google’s Mobile Friendly test. Google offers these basic guidelines for making your site mobile-friendly:

• Avoid Flash and other software that’s not compatible with mobile devices.
• Use large text that is readable without zooming in.
• Use screen-sized content that doesn’t require users to scroll or zoom.
• Allow space between buttons and links for easy tapping.