Responsive website tester (see it on phone, tablet and desktop)
Enter the website address and choose the screens. Each frame has the real width of the device, scaled down to fit here.
How to useYour site on several screens at once
Available in: 
Responsive website tester (see it on phone, tablet and desktop): what it is for
Before publishing, check that your site works on screens of every size. Enter the address and see the site side by side on a small phone (360 px), iPhone SE (375 px), iPhone 15 (393 px), tablet (768 px), laptop (1366 px) and Full HD (1920 px), each at its real width and scaled down to fit the screen.
Rotate to landscape, create a custom width and reload all the frames at once. It works with your localhost and with sites that allow being opened inside another one; those that block it for security (X-Frame-Options) appear blank, and the page explains why.
How to use
- Enter the website address.
- Choose the screens and the zoom.
- Scroll between the frames and check the layout.
When to use it
- Checking a site before publishing.
- Showing a client how it looks on a phone.
- Testing media queries.
Frequently asked questions
Why do some sites show up blank?
Many sites (Google, Instagram, banks) send a security header (X-Frame-Options or frame-ancestors) that forbids them from appearing inside another site, to prevent clickjacking scams. Your own site normally works; if it doesn't, it has this protection too, which is a good thing.
Is it the same as viewing on a real phone?
The width is the same, so the layout, media queries and line breaks look the same. What changes is the touch behavior, the system font and the pixel density.
Can I test a site that is still on my computer?
Yes. Enter the local address, such as http://localhost:3000.
Is it really free?
Yes, 100% free. No sign-up, no subscription and no usage limits. All Tools123 are free.