Mobile display size
320x100 — Large Mobile Banner
Also called Double banner.
- Width
- 320px
- Height
- 100px
- Aspect ratio
- 16:5
- Area
- 32,000px²
Actual size
Rendered at true pixel dimensions. On a narrow screen it scales down to fit.
Where it runs
Inline within mobile content, or as an anchored unit.
Why it is used
Twice the height of a standard mobile banner, giving genuinely usable creative space while staying compact. It generally outperforms 320x50 on both CTR and CPM, which makes it worth supporting wherever the layout allows.
What to watch for
Demand is thinner than for 320x50 because fewer advertisers produce the size. Accept both on the same slot rather than choosing between them.
File weight for standard display is commonly specified at around 150 KB initial load, but publisher specs vary and the figure that governs is always the one written into the insertion order. Check it before trafficking rather than after a creative is rejected.
Related sizes
Dimensions follow IAB Tech Lab display guidelines. Placement and performance guidance is practitioner knowledge, last verified July 2026.