Replacement lamp globes come in a variety of sizes the globe diameter will range from 8" to 12". These sizes will all have a 4" bottom openings and a 3 1/4" top opening for the chimney to rise through. When measuring our globe, measure vertically from the very bottom to the very top. The is a 1/2" difference in the height and diameter. An 8" globe will have a vertical height of 7 1/2". We also stock a variety of globe without a top opening.