Since it’s slightly different to the “normal” sizes:
- Banner: 468×49
- Leaderboard: 728×79
- Square: 250×239
- Small Square: 200×189
- Large Rectangle: 336×269
- Medium Rectangle: 300×239
- Skyscraper: 120×578
- Wide Skyscraper: 160×578
The slight difference in size is to cover the space used by Google themselves
