10cm - 20cm. Leaves can grow up to 12cm long.
A typical succulent, with a wide range of habitats in its native South Africa - from exposed dry sandy conditions to upland grassland and even forest margins. It is remarkably hardy and can grow outside in milder parts of UK (it is frost hardy to -7C, but needs to be protected from wet conditions, and plants bought as houseplants would need to be gradually hardened off for use outdoors).
It is an ideal plant for a sunny windowsill or conservatory.
Like most succulents, it requires a period of darkness every day.