You've heard it a thousand times. "Mobile first." And yes, the numbers back it up - most website traffic comes from phones. We know this and all analytics point to this.

But, the person who actually signs the cheque at larger organisations and businesses: the director, the procurement head or the CEO, may not squint at your website on a cracked iPhone screen during their commute. They're sitting in a boardroom, or behind a vast curved ultrawide monitor, or they've thrown your site up on a 65-inch screen to discuss with the rest of the leadership team.

And on that screen, your beautifully mobile-optimised website could look like a stretched-out mess.

Do big decisions get made on big screens?

Think about how buying decisions get made in big businesses. Someone junior does the initial research, probably on a phone or laptop. They make a shortlist and then they present that shortlist to the people with authority.

That presentation happens in a meeting room, on a big screen. Your website is up there next to your competitors and both the websites, and what they say about your business, are being judged in seconds.

If your site looks thin, washed out, poorly proportioned or just plain amateur at that size, you may have lost and not because your product is worse, but because the visual impression of what you offer said so before a single word was read.

What could go wrong on a large screen?

Most websites are built with a maximum content width, often around 1200 or 1400 pixels. Beyond that, the content sits in the middle of the screen with vast empty margins on either side and on a standard desktop monitor, this is fine. On a 34-inch ultrawide or a boardroom television, it looks like a postage stamp on a tablecloth.

Other common problems at large sizes include:

• Text that becomes tiny relative to the screen - making the page feel sparse and unfinished.
• Images that either stretch and pixelate, or stay small and look lost.
• Navigation bars that spread too wide and lose all visual logic.
• Hero sections that were designed to look dramatic at 1440 pixels and look completely flat at 2560 or beyond.
• Call-to-action buttons that shrink to irrelevance when the surrounding space expands.

The irony is that these are exactly the kinds of problems we obsess over on mobile, and then completely ignore at the other end of the scale.

How to test your website on a larger screen

You don't need a boardroom television to check this. Here are practical ways to see what your site looks like to the people who matter most.

The browser zoom-out test

Open your website in Chrome, Firefox or Edge. Now hold Ctrl and press the minus key (on a Mac, hold Cmd and press minus). Each press zooms the page out by 10%. Try 90%. Then 75%. Then 67%. Then 50%.

What you're simulating is how your site appears on a larger display relative to the content. A 27-inch monitor at 100% zoom shows roughly the same content width as a standard laptop at 75% zoom. A large boardroom screen at native resolution is closer to 50% or even 33%.

Watch what happens to your layout as you zoom out. Does it hold together? Does the text remain readable? Do the images scale sensibly? Does the page still look like something you'd be proud to show a client?

If it starts to look broken, sparse or embarrassing below 75% - you have a problem worth fixing.

Use browser developer tools

In Chrome, press F12 to open developer tools. Click the little screen icon at the top left of the tools panel - this opens the device toolbar. You can type in any custom resolution you like. Try 2560 x 1440 (a common large monitor). Try 3440 x 1440 (a popular ultrawide). Try 1920 x 1080 at 150% browser zoom, which is how many people actually use large screens.

Check on an actual television if you can

Most modern televisions have a browser built in, or you can connect a laptop via HDMI. Pull up your site and your top three competitors. Stand back six feet and look at all four.

Pay attention to which sites look authoritative and which look like they were designed by someone who never considered this moment.

What does good large screen website design actually look like?

The fix is not simply making everything bigger, because that creates its own problems. The goal is a layout that scales with intelligence.

This means using fluid typography - type that grows proportionally as the viewport widens, rather than staying fixed at a size that made sense on a laptop.

It means thinking about maximum content widths carefully. Some sections, particularly full-width imagery and video, can and should extend to the full screen width. Text columns should not. A line of body text that runs 1800 pixels wide is unreadable. Constraining text to a comfortable reading width while allowing surrounding elements to breathe is a design decision, not an accident.

It means testing hero sections at ultrawide ratios. A background image that looks perfectly composed at 16:9 may crop badly at 21:9, cutting off faces, losing the focal point, or leaving the subject stranded in a corner.

It means ensuring your navigation makes sense when it has more horizontal space, not less. Menus that collapse elegantly on mobile sometimes sprawl incoherently when given room to spread.

What to do next

Open your website and press Ctrl+minus four times and look at what you see.

If you're happy with it, good. If you're not, and most people won't be, that's the conversation worth having with your web agency.

Because the person signing the contract might not be looking at a phone.