A fitting room for websites

Does your site actually fit?

Paste any URL or your localhost. We try it on every screen at once and tell you, bluntly, where it spills.

Works with localhost, staging, and anything that lets itself be framed. Some sites are shy.

The fitting, explained

How it works

Paste your website. See it on phones, tablets, laptops and big screens at the same time, at their real sizes. No sign-up. Nothing to install.

  1. Paste your link

    Type your website’s address in the box and press Try it on.

    Your live site works, like mysite.com. So does the site you’re still building, the address Claude gives you when it runs it on your computer, like localhost:3000.

  2. Look at every screen

    Each box is a real device. Your actual site is loaded inside every one, so you can scroll and click like normal.

    The boxes are shrunk so they fit on your screen, but your site doesn’t know that. It thinks it’s on the real phone, so what you see is what people get.

    Tap + to add more devices (123 real ones: iPhones, Samsungs, Pixels, iPads, MacBooks, big monitors). Tap a device’s name to see it big.

  3. Read the stickers

    Every screen gets a sticker that tells you, bluntly, how your site fits.

    FITS
    Nothing sticks out. You’re good.
    TIGHT
    Text is touching the edge of the screen, or getting cut off. It probably wants a bit more space.
    SPILLING +24PX
    Something is 24 pixels too wide, so people can drag the page sideways. Everyone hates that. Tell Claude: “on phones something is 24px too wide, please fix it.”
    BLOCKED
    That website doesn’t let other sites show it. Not your fault. See the questions below.
    not measured
    We can show the site, but we’re not allowed to measure it. Step 4 fixes that.

  4. Get the stickers on your own site (one copy-paste)

    For safety, a website isn’t allowed to look inside another website. So your site has to tell us its own size. You set that up once, by adding one line to your site.

    The easy way: copy this message, paste it to Claude, done.

    Is it safe? Yes. The line does nothing for your normal visitors. It only wakes up when your page is open inside doesitfit, and all it says is how wide things are.

    Message for Claude

    Or add the line yourself, inside <head>

    <script src="https://truesize.vercel.app/measure.js" async></script>

Questions people ask

Do I have to install something?

No. To see your site on every screen, just paste the link. The only optional extra is the one line from step 4, and only if you want the stickers.

A screen is blank or says BLOCKED. Did I break something?

No. Some websites (GitHub, banks, big brands) refuse to be shown inside other websites. Your own site usually allows it.

My localhost site won’t show up

localhost means “this computer”. On this website it works in Chrome: when Chrome asks to let the site see devices on your network, click Allow. Safari doesn’t allow it.

How exact is it?

The sizes are exact. Each box is the real width and height a website gets on that device. We researched every one of the 123 devices.

A few small things only a real phone can show you:

  • Fonts can look a tiny bit different, because phones use their own fonts.
  • Hover effects still show up. Phones don’t have a mouse.
  • Images can look sharper or softer, because your screen isn’t a phone screen.
  • On a real phone, the browser’s bars shrink when you scroll. Turn on Browser bars to see the space a visitor has at the start.
  • If your computer always shows scrollbars, they take about 15px off each box. On a Mac: System Settings → Appearance → Show scroll bars → When scrolling.
What do the buttons do?
Rotate
Turns phones and tablets sideways.
Browser bars
Adds the phone’s top bar and the Safari/Chrome bar, so you see the space a visitor really has.
Mockups
Draws the real phone around the screen: frame, buttons, the camera cut-out.
Sync scroll
Scroll one screen and they all scroll. Needs the stickers working (step 4).
Zoom
Makes the boxes bigger or smaller. It never changes how your site looks inside them.
Share
Copies a link to exactly what you’re looking at, so you can send it to someone.
Local proxy
Only on the version running on your computer. Gets past blocked sites and measures everything.