# Predictability Of Minecraft Seeds

In a nutshell, is there anyway to predict what kind of landscape a certain seed will generate?

I've done some research and seems like the answer is no, but is there some sort of general guideline, like seeds with just letters results in largely desert landscapes or that negative numbers as seeds result in large tundra biomes.

Thank You!

• I'm not a minecraft player; I just wanted to comment that if this seed is used as its name suggests - as a seed for a pseudo-random-number-generator - then the answer will be "no", you cannot find any predictable relation between seed value and generated terrain.
– Oak
Apr 26, 2011 at 5:59
• possible duplicate of Minecraft seeds for a high landscape? Apr 26, 2011 at 13:21
• As far as I know landscapes are generated using a highly tweaked version of 2D (maybe 3D?) Perlin noise, so if you knew the hash function that converts seeds into an internal integer and you knew exactly how Notch tweaked Perlin noise then yes, you could determine the landscape by generating it yourself. Then again, even if you knew this it's easier to generate the map and browse it in Cartographer G. Apr 26, 2011 at 14:13
• @Oak yes, that is exactly what the seed is for, but it is a pseudo random number generator we are talking about here. And knowing the kind of people that frequent this website I just thought that it wouldn't be all that surprising if somebody would have figured out the algorithm or perhaps created some close approximation. Apr 26, 2011 at 23:05
• Also, @Sadly Not if that were an answer I would accept that as the correct one. :] I just don't know how I didn't think of a map editing software to begin with... I guess I was looking for some way to have a certain type of landscape, but still have the generated world be somewhat unique and random. Apr 26, 2011 at 23:07

As Oak has said, the seed is used to seed a pseudo random number generator, which makes it (in practice) impossible to determine. However, to make things worse, the given seed is first run through a hash function ( http://en.wikipedia.org/wiki/Hash_function ) that (should) generate wildly different values with the changing of 1 letter.

In short, there is no useful correlation between the seed input ("Gargamel" for example) and the seed used (some number). And even if there was it wouldn't get you very far.

Update (for clarification):

This does not mean that using the same seed will generate a different map (else sites like minecraftseeds.info wouldn't work), the hash function will always generate the same output given the same input and the pseudo random number generator will always create the same sequence from this number. It does mean however, that changing one bit of the seed (say, "Gargamel" versus "Gbrgamel") will create a different map, which will usually have very little in common with the first map.

• Is this (minecraftseeds.info) website not based on the idea that using the same seed will provide you the same map? Apr 26, 2011 at 23:01
• @chands Using the same seed twice will give you the same map each time, but the point Yourdoom is making here is that if you change one character in the seed, it will produce a completely different map. Apr 27, 2011 at 1:00
• Okay, I guess I see the point here. Thank you for your patience and great comments everyone! Apr 27, 2011 at 4:59
– Elva
Apr 27, 2011 at 8:55
• Well, technically its possible that it's the same map (hash collisions and all that) but in all likelihood the differences will be far greater that the similarities, but you are right, I'll change the language a bit.
– Elva
Apr 28, 2011 at 11:14

The short answer is 'No', as you already found out through your research. A common property of most (pseudo-)random generators, including the one used by Minecraft terrain generator, is that 'similar' seeds give wildly different results.

There is no way of predicting that e.g. negative numbers will produce certain features more often. As for the letters in the seed - if the seed contains them, the string is converted to a numerical seed using a certain calculation (`String.hashCode()` to be exact).

That said, there is some difference between numerical seeds and seeds with letters, but it has almost no practical implications: numerical seeds are 64 bit numbers, while seeds with letters are hashed to a 32 bit number. This means that there are 18 quintillion possible Minecraft worlds, but if you use a seed with a letter in it, you can generate 'only' 4 billion of them.

• Don't forget that you can create some other text that results in the same hashcode as a given text and will thus result in the same seed. Jun 13, 2014 at 9:53

It's possiple to predict by a loading screen. The dark oak forest, tundra, extreme hills, jungle are loading slower, than the desert, plains and deep ocean, savanna; because of a lot of blocks around you. And different seeds have the different loading screen, so, in practice, loading screen can tell you enough about next seed, if you know patterns.

Second thing -- MineAtlas. But if you know the seed, it can help you to find the biomes and structures. A big problem: it's very-very slow and banned in speedruns.

Don't know any other ways, btw. Maybe there's an another ways. Google "Seed Theory" and check, that other people thought. I hope, that helps.