What is the 300x250 ad size called?

300x250 is the Medium Rectangle, often abbreviated MPU. It is the most widely trafficked display unit and fits both in-content and sidebar placements on desktop and mobile.

Which IAB ad sizes are considered standard high-impact units?

The IAB New Ad Portfolio highlights flexible and high-impact units such as the 970x250 Billboard, 300x600 Half Page, 300x1050 Portrait and 970x90 Large Leaderboard, alongside the universal 300x250 and 728x90.

How is the aspect ratio of an ad unit calculated here?

The tool reduces the width and height by their greatest common divisor, so 300x250 shows as 6:5 and 728x90 shows as 364:45. It is display-only and does not change the pixel dimensions.

What are the common mobile banner sizes?

The standard anchored mobile units are 320x50 Mobile Banner and 320x100 Large Mobile Banner, plus full-screen 320x480 and 480x320 interstitials for phones and 768x1024 for tablets.

Why does a 1x1 size appear in the reference?

1x1 is a placeholder size used for native, interstitial and tracking-pixel requests where no fixed-size creative renders. It is included so you can recognize it in bid requests and ad tags.

IAB Standard Ad Size Reference

Look up IAB and common programmatic ad-unit sizes — name, dimensions and aspect ratio — and search by name or WxH in your browser.

The IAB Standard Ad Size Reference runs entirely in your browser. The names and dimensions you search are matched against a bundled table on your device and nothing is uploaded to ArrayKit.

Open the OpenRTB Enum Reference

About IAB Ad Size Reference

The IAB Standard Ad Size Reference is a searchable table of the display and mobile ad units you actually traffic — 300x250 Medium Rectangle, 728x90 Leaderboard, 320x50 Mobile Banner, 300x600 Half Page, 970x250 Billboard, 160x600 Wide Skyscraper and more — each with its human name, pixel dimensions, aspect ratio and a note on where it is used. Type a name like leaderboard, an alias like MPU, or a dimension like 300x600, and it filters instantly; category chips narrow to Universal, Desktop, Mobile or Special units. Ad-ops managers, publishers, and Prebid or Google Ad Manager engineers can confirm a size, grab the WxH, and stop second-guessing which unit maps to which name. Everything runs in your browser, so nothing you search is uploaded.

Features

Bundles IAB standard and common programmatic units from 300x250 to 970x250, 300x1050 and 1x1
Each row shows the name, exact WxH, computed aspect ratio and a usage note
Search by name, alias (MPU, Half Page), category, or a WxH string like 728x90
Category chips filter to Universal, Desktop, Mobile or Special ad units
Proportional thumbnail previews the shape of every unit at a glance
Copy any dimension string with one click to drop into an ad slot or size mapping
Includes legacy and high-impact units — Billboard, Portrait, Panorama, Netboard, interstitials
Runs entirely in your browser so the terms you search never leave your device

How to use the IAB Ad Size Reference

Type a name, alias, or a WxH like 300x250 into the search box
Or tap a category chip to browse Universal, Desktop, Mobile or Special units
Read the dimensions, aspect ratio and usage note for each unit
Copy the WxH string and paste it into your ad slot, size mapping or Prebid config

Example

Input

leaderboard

Output

728x90  Leaderboard  ·  364:45  ·  Desktop

Search a name to get the exact dimensions and aspect ratio.

Common errors & troubleshooting

You reserve 300x250 but call it a Leaderboard in the trafficking sheet. — 300x250 is the Medium Rectangle (MPU). The Leaderboard is 728x90. Match the name to the WxH here before you traffic the line item.
A creative renders cropped inside its slot. — Confirm the creative WxH exactly matches the slot size and aspect ratio — a 300x600 Half Page will not fit a 300x250 Medium Rectangle slot.
Mobile fill is low on a 728x90 unit. — 728x90 is a desktop Leaderboard. Phones use 320x50 Mobile Banner or 320x100 Large Mobile Banner — add those to your size mapping for mobile devices.
You see a 1x1 size in a bid request and expect a rendered creative. — 1x1 is a placeholder used for native, interstitial and pixel requests where no fixed-size creative renders. Treat it as a signal, not a display unit.

Frequently asked questions

What is the 300x250 ad size called?: 300x250 is the Medium Rectangle, often abbreviated MPU. It is the most widely trafficked display unit and fits both in-content and sidebar placements on desktop and mobile.
Which IAB ad sizes are considered standard high-impact units?: The IAB New Ad Portfolio highlights flexible and high-impact units such as the 970x250 Billboard, 300x600 Half Page, 300x1050 Portrait and 970x90 Large Leaderboard, alongside the universal 300x250 and 728x90.
How is the aspect ratio of an ad unit calculated here?: The tool reduces the width and height by their greatest common divisor, so 300x250 shows as 6:5 and 728x90 shows as 364:45. It is display-only and does not change the pixel dimensions.
What are the common mobile banner sizes?: The standard anchored mobile units are 320x50 Mobile Banner and 320x100 Large Mobile Banner, plus full-screen 320x480 and 480x320 interstitials for phones and 768x1024 for tablets.
Why does a 1x1 size appear in the reference?: 1x1 is a placeholder size used for native, interstitial and tracking-pixel requests where no fixed-size creative renders. It is included so you can recognize it in bid requests and ad tags.

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