Desktop display size
300x600 — Half Page
Also called Filmstrip, Large skyscraper.
- Width
- 300px
- Height
- 600px
- Aspect ratio
- 1:2
- Area
- 180,000px²
Actual size
Rendered at true pixel dimensions. On a narrow screen it scales down to fit.
Where it runs
Sidebar, usually sticky so it remains in view while the page scrolls.
Why it is used
The highest-impact standard display unit. Its size and sticky placement give it strong viewability and unusually good performance for brand campaigns, and it commands premium CPMs. Publishers like it because one slot fills a large share of the sidebar.
What to watch for
Desktop only in practice, and its height means a slow-loading creative is very visible when it fails. Sticky implementations also need care: a unit that follows the user for the whole session can breach frequency expectations and is a common source of complaints.
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.