Seed (level generation)

A seed is a code used in Minecraft's world generation process. Each world has its own seed value which is used to keep generated terrain consistent, as generation is pseudo-random. Prior to Beta 1.3, seeds were automatically generated per-world. Since then, the player can input their own seed, which is not limited to numbers due to the use of the Java function. For instance, a seed of "abc" is converted to the numeric value.

Using the same seed to generate two separate worlds will generate the same terrain consistently, even on different systems. As such, seeds can be shared by players to generate the same world between them. However, the player's initial spawn point will be random; it is not tied to the seed value.

If you leave the seed blank, the game will use the time as a seed. A blank seed will not produce the same map every time.