Banner.w

Width of the slot in device-independent pixels. Through 2.4 the spec marked it recommended in all cases; from 2.5 it is an exact width, recommended only when no Banner.format list is sent.

CurrentintegerOptionalSince 2.0

Field facts

Path: imp.banner.w, imp.audio.companionad.w, imp.video.companionad.w
Object: Banner
Type: integer
Requirement: Optional
Added: OpenRTB 2.0
Spec section: 3.2.6

How it is used

In 2.4, w and h were a preferred size when a format list was present and an exact size when it was not. Device-independent pixels are not physical pixels: a 320 by 50 slot on a high-density phone screen is still 320 by 50.

Example

Where the field sits in a payload, with everything else left out:

{
  "id": "req-1",
  "imp": [
    {
      "banner": {
        "w": 300
      }
    }
  ]
}

Common mistakes

Sending physical pixels from a high-density screen, such as 960 by 150 for a 320 by 50 slot, so no standard creative fits.
Sending a width that matches none of the sizes in Banner.format, which leaves the buyer to guess which size is real.

Version history

Added in OpenRTB 2.0, and present in the latest snapshot. The table shows how each version's spec text types the field.

Versions	Type in the spec	Required	Deprecated
2.0 to 2.2	integer	Recommended	No
2.3 to 2.4	integer	Recommended	No
2.5 to 2.6-202606	integer	No	No