30-40cm. Up to 8m in the wild. Houseplants are typically 60cm - 2m
"In the wild, this plant grows on sandy riverbanks and damp forest clearings in the warm, wet forests of Eastern Madagascar. It requires good light and can tolerate direct sunlight through a window or conservatory. It also requires warmth, so should not be exposed to temperatures below approx. 15C.
Dypsis lutescens benefits from high humidity, and regular misting of the foliage with tepid water will help keep it looking fresh and also deter two-spotted spider mites "