[ni-ch]

The number of keys you need depends on what you will be using them for.

88 keys is considered the professional standard, and it is the same number of keys on a grand piano. Most classical and serious compositions will be written for an 88 key keyboard.

61 keys is more common in the pop, rock, and electronic music world, and it is generally a bit more affordable and portable. Many people find 61 keys enough for their needs, especially when they are first starting out.

If you are not sure, 61 keys would be a good place to start. You can always upgrade later if needed.