In just a couple weeks, Google is going to make a significant change to its ranking formula. The objective of this change is to reward mobile-friendly websites with higher search result rankings.

We know this because Google has come out and said it directly.

The original announcement took place on Google's webmaster blog: "Starting April 21, we will be expanding our use of mobile-friendliness as a ranking signal. This change will affect mobile searches in all languages worldwide and will have a significant impact in our search results. Consequently, users will find it easier to get relevant, high quality search results that are optimized for their devices."

There are a couple key points to this:

“Mobile-friendliness as a ranking signal,” and “[this change] will have a significant impact in our search results."

For a company that keeps its cards close to its chest when it comes to ranking formulas, this type of statement carries massive weight.

Google put together a guide explaining how you can prepare for “Mobilgeddon," but it’s not your job to read these types of things (it’s mine). So here’s what you need to know about Google’s upcoming algorithm change and how it could affect your website’s rankings.

What does “mobile-friendly” mean?
A mobile-friendly website is a website designed specifically for use on a smartphone device.

Smartphone screens are roughly 1/5th the size of desktop screens, so they require more concise messaging, design, and coding. Instead of using a mouse for navigation, users rely on their fingers, which requires larger buttons. Mobile users are often on the go, therefore they need information quickly. Properly coded websites will minimize load times and provide a faster user experience.

These attributes, among others, make for a mobile-friendly website.

What does a mobile site look like?
Let’s start with what it doesn’t look like. A mobile-friendly site does not look like a desktop website compressed onto a four inch screen. This requires the user to pinch and zoom in order to read the page content (everyone has experienced this frustration). By comparison, a mobile-friendly website fits naturally onto a small screen, uses larger text, and can be browsed effectively with even the fattest of fingers.

You can usually determine if a website is mobile-friendly based on your personal experience. If a website is difficult to read and impossible to navigate with just your thumb, it’s not mobile-friendly. If you are able to accomplish what you need without squinting or resizing the page, it’s likely mobile-friendly.

How do you achieve mobile friendliness?
Making a website mobile-friendly will require a web developer and an investment. The sophistication of your website, the number of pages, and its platform (e.g. Wordpress, Joomla, Drupal) will affect the size of that investment. Prepare to spend anywhere from $3,000 to the low five digits to convert a non-mobile friendly site into a mobile-friendly one.

Most web developers automatically build mobile-friendliness into their new site designs in 2015. If you’re in the process of developing a new website, check with your web developer to make sure this is the case.

Is it important to design specifically for tablets as well?
No. A website that looks great on a desktop will function just as well on a tablet. Also, Google says it will not differentiate between the two.

How can I tell if my site is mobile-friendly to Google?
Google offers this free tool to test your site for mobile-friendliness. If your site passes this test, you’re in good shape (as far as Google and April 21st are concerned).

What happens if I don’t make my site mobile-friendly?
It reasons to say that if Google rewards sites for being mobile-friendly, non-friendly mobile websites will have a more difficult time ranking after April 21st. Only time will tell by how much, but expect to see a drop in rankings and less traffic as a result.

Google and rankings aside, if you’re not considering how to maximize your mobile users’ experience, you are alienating an ever-growing segment of your website traffic.

Why does Google care so much about mobile?
Per Google, "94% of people with smartphones search for local information on their phone, [while] 77% of mobile searches occur at home or at work, places where desktop computers are likely to be present."

While desktops will not go extinct any time soon, the number of users who treat their smartphone as their primary internet device is continuing to grow.

That’s a pretty scary thought, if you aren’t taking your mobile experience seriously.

Mobile has become, and will continue to be, a wildly important topic for any business with an online presence. Adapt now, or be left in the dust (and off the first page of search results).