Every responsive design company will tell you its websites work on phones. The good news is you do not have to take their word for it. In about ten minutes, with your own phone and a free Google tool, you can test an agency's past work and see whether it holds up. This guide explains what responsive design means in plain words, gives you a step-by-step test to run on any responsive website design company's portfolio, the questions to ask before you sign, the red flags to walk away from, and what it should cost.

I'm Robert P. Dickey, President of AQ Marketing in Woburn, Massachusetts. We have built websites for small businesses since 2003, and the test below is close to the one we run on our own sites before launch.

What "responsive" means, in plain words

A responsive website is one site that rearranges itself to fit whatever screen it is on: a wide desktop monitor, a tablet, or a phone. Columns stack, menus fold into a button, images shrink, and text stays readable without pinching or zooming. There is one address and one set of content, not a separate "mobile site."

The idea has a clear origin. Web designer Ethan Marcotte named and described it in his article "Responsive Web Design" in A List Apart, published May 25, 2010. It has been standard practice ever since, which is exactly why "we do responsive design" is no longer a selling point. The question is how well a company does it.

It also matters for search. Google says it uses the mobile version of a site's content for indexing and ranking, which it calls mobile-first indexing (see Google's mobile-first indexing guide). If something is missing or broken on the phone version of your site, Google may not see it either.

The 10-minute test: check any company's portfolio yourself

Pick three sites from the company's portfolio, ideally ones built in the last two years for businesses like yours. Then run these checks. You need a phone, a computer, and a notepad.

1. Open each site on your phone first (2 minutes)

Look at the first screen without scrolling. Can you tell what the business does, where it is, and how to contact it? Is there a visible phone number or button? If the first thing you see is a giant image with no words, or a pop-up covering the page, note it.

2. Tap everything that matters (2 minutes)

Tap the menu button, a few menu links, the phone number and the main call-to-action button. Buttons should be easy to hit with a thumb without tapping the wrong thing. For reference, the web accessibility standard WCAG 2.2 sets a minimum target size of 24 by 24 CSS pixels for most tap targets (W3C's explanation of target size). If you keep mis-tapping, so will customers. The phone number should open your dialer when tapped.

3. Fill out a form (2 minutes)

Start the contact or quote form on your phone. Does the right keyboard appear (numbers for the phone field, the @ key for email)? Are the fields big enough? Can you see the submit button without the keyboard hiding it? Do not submit fake details to a real business. Just check that the form is usable, then back out.

4. Check text and images (1 minute)

Can you read the body text comfortably at arm's length without zooming? Do any images or tables spill off the right side of the screen and make the page scroll sideways? Sideways scrolling on a phone is one of the clearest signs of a sloppy build.

5. Resize on a computer (1 minute)

Open the same site on a computer and slowly drag the browser window from full width down to narrow. The layout should change smoothly. Watch the in-between widths, around tablet size, where many sites break: overlapping text, a menu that wraps onto two lines, or a hero image that crops out the important part.

6. Run a speed test (2 minutes)

Paste the site's address into Google's free PageSpeed Insights and look at the mobile results. The key numbers are the Core Web Vitals. Google's Core Web Vitals guidance says a good experience means Largest Contentful Paint (how fast the main content appears) within 2.5 seconds, Interaction to Next Paint (how fast the page reacts to a tap) of 200 milliseconds or less, and Cumulative Layout Shift (how much things jump around while loading) of 0.1 or less. Scores move a little from test to test, so look at the overall picture rather than one number.

Write down what you found for each site. If two out of three portfolio sites fail basic checks, you have learned more than any sales call will tell you.

How we check every page before launch

We hold our own work to the same test. At AQ Marketing, every page of a new site is checked in a real browser at three widths before it goes live: desktop (around 1,440 pixels wide), tablet (around 768) and phone (around 390). We look at the same things listed above: the first screen, the menu, tap targets, forms, text size, images that overflow, and page speed. We fix what we find before the page goes live.

We do it this way because design tools and code previews can hide problems that show up instantly on a real screen. The problems this kind of check is built to catch are usually the boring ones: a button label that wraps onto two lines on a phone, a table that is too wide, a photo that crops a person's head off at tablet width. None of them are hard to fix. They only get missed when nobody looks.

Questions to ask a responsive design company

Ask these before you sign anything. Good companies answer them easily.

  • How do you test on phones and tablets before launch? Listen for real devices or real browsers at specific widths, not "our theme is responsive."
  • Can I see three recent sites for businesses like mine? Then run the 10-minute test on them.
  • Who writes the content? Copy that reads well on a phone is short and direct. If you are writing it all yourself, plan for that time.
  • What happens to speed after launch? Sites get slower as photos and plugins are added. Ask who watches that.
  • Who owns the site and the domain? You should. Get it in writing.
  • What does the monthly cost include? Hosting, updates, security, small edits, and support should be spelled out.
  • How are forms and calls tracked? A site that looks good but cannot tell you where leads come from is hard to improve.

Red flags

  • A separate "mobile site" on a different address (like m.yoursite.com). That approach is outdated and doubles the work.
  • Portfolio sites that fail the 10-minute test. Their past work is the best preview of your site.
  • No live links in the portfolio, only screenshots. Screenshots hide how a site behaves on a phone.
  • Vague answers about testing, or a promise that a template "handles all that automatically."
  • The company keeps your domain or site if you leave.
  • Guaranteed rankings. No honest company can promise a Google position.

What a responsive website should cost

Price depends on how many pages you need, who writes the copy, and what is included after launch, so be careful comparing quotes line by line. A one-time build fee with no hosting or support is a different product from a monthly plan that covers everything.

As one concrete example, our own web design service is included in our Smart Website and Marketing Package at $500 a month on a 12-month agreement. That covers custom mobile-first design, copywriting, speed work for Core Web Vitals, local SEO setup, hosting and maintenance, and you own the site, domain and data. It also includes an AI chatbot and AI voice receptionist, which carry per-minute usage fees. That is one way to package it, not the only one. Whatever you are quoted, ask what is included, what costs extra, and what you keep if you leave.

If you are planning a WordPress site specifically, our guide to responsive WordPress website design goes deeper into themes, page builders and speed on that platform.

Frequently asked questions

What does a responsive design company do?

A responsive design company builds websites that adjust their layout to fit desktops, tablets and phones from one set of content. A good one also tests each page on real screens, keeps the site fast, and makes forms and buttons easy to use on a phone.

How can I tell if a website is responsive?

Open it on your phone and look for readable text without zooming, a menu that folds into a button, no sideways scrolling, and buttons you can tap easily. On a computer, narrow the browser window and watch whether the layout rearranges smoothly.

Does responsive design help with Google rankings?

It helps indirectly. Google indexes the mobile version of your site, so content that is missing or broken on phones can hurt you. A fast, usable mobile site also keeps visitors on the page. Responsive design alone does not guarantee rankings; content and local SEO still matter.

How long does a responsive website take to build?

It depends mostly on page count and how quickly content and approvals come in. Ask any company for a timeline broken into steps (review, design and copy, build, testing, launch) and who is responsible at each step.

Is a responsive website design firm better than a website builder?

Most modern website builders produce responsive layouts, so the difference is less about the technology and more about the testing, copy, speed work and ongoing care a firm adds. If you have the time to test and maintain the site yourself, a builder can work.

If you would rather have someone else look at your current site, ask for our free 20-point local audit and mention you want it checked on phone, tablet and desktop. See our web design services, browse the websites in our portfolio and test them yourself, or contact AQ Marketing at (781) 404-3147.