Live Viewport Size

See your live browser viewport dimensions in real time as you resize the window. 100% free, private, and browser-based — no sign-up. 100% free and private.

which excludes the scrollbar.

Why is mobile viewport so small?

Mobile uses CSS pixels, not physical. A 1179px iPhone shows as 393px.

Will it work in an iframe?

Yes, but reports the iframe's viewport, not the parent's.

Is anything stored?

No. All values are read live in your browser.