How far do I have to place torches so that mobs will not spawn near me?

Question

Since torches prevent mobs from spawning, is it possible to place enough torches within a specific radius to ensure safety during the night? I'm thinking of a situation without any shelter built, more along the lines of a flat plain. If it is possible, how many torches/how far out do I need to go to make that area safe?

Answer 1

1. Learn about light:

   • Sunlight gives 15 luminance to the blocks it hits directly, or through half steps.
   • Lava gives 15 luminance.
   • Lightstone gives 15 luminance.
   • A jack-o-lantern gives 15 luminance.
   • A candle gives 14 luminance to the otherwise empty block it occupies.
   • A redstone candle gives 7 luminance to the otherwise empty block it occupies.

   • Every tile that isn't a light source has a luminance of one minus the luminance of its neighbors. For example, if you had a 6 and a 4 luminance sources close to each other, attached to a wall, you'd have this distribution:

                 1
                121
           1   12321
          121 1234321
         1232123454321
        123432345654321
         12┴─────┴4321
          1     12321
                 121
                  1  
     

     ...except this works in three dimensions instead of two!

2. Learn about spawning:

   1. The following applies to any difficulty, except for Easy.
   2. Every tile within 24 distance of the player is not eligible.
   3. Every tile outside a 144×144 square centered on you is not eligible.
   4. • Every non-glass, non-half step surface in the outer world with 7 or less luminance is eligible for spawning.
      • Every non-glass, non-half step surface in the Nether is eligible for spawning.
   5. Mob spawners cause mob to spawn at a high rate in any surface within 5 distance of it.
      
      

3. In practice:

   Here's what I try to do to ensure a luminance of 7 consistently along a line:

   1. Place the first torch. Pardon my hexadecimal one-sided luminance graph:

      EDCBA98765432100000000000000000
      ↑
      

   2. Proceed until you find two tiles looking exactly like the next, then go back one.

      EDCBA98765432100000000000000000
                   ↑
      

   3. Plant a torch there. Lo and behold, minimum luminance there will be 8!

      EDCBA9889ABCDEDCBA98765432100
                   ↑
      

   4. GOTO 1

   You can adapt this algorithm to your necessities with ease. Just plant a torch in the darkest area when in doubt. (Duh.)

   Also:

   • Put torches directly onto surfaces for best results.

   • In your mining, be aware that any surface is good enough to spawn...

     ↓↓↓ ↓↓    All positions marked with an arrow are valid
     ███ ██↓   spawning points, to the best of my knowledge,
     █     █↓  and they all can lead to the just spawned mob
     █      █  to reach you.
     █     ↓█
     █↓↓↓↓↓█   Be vigilant and don't mine caves from the
     ███████   bottom up :(
     

4. Learn how to keep mob that has spawned outside: make traps.

   • Mobs can only jump up one tile. Make pits deeper than that and, once in, they will be trapped (skeletons are still dangerous and spiders can climb out).
   • Mobs cannot deconstruct. Make walls. (Be aware creepers do explode, if they get close enough.) Use cobblestone: they have high explosion resistance and can't catch fire.
   • Mobs cannot use items. Protect your entrance with a wooden door. Plant it from the outside, or skeletons will be able to hurt you with their arrows!
   • Mobs' path finding is somewhat dumb. Protect your spawn point with water and liberal amounts of cactus (arrange them in a chequered pattern.)

Answer 2

Torches Provide a light level of 14. Note that this is to the block that they are in. Adjacent blocks have a light level of 13. Mobs require a light level of 7 or less to spawn. This means that mobs can't spawn within 7 of a lit torch. So placing a torch every thirteen tiles will keep a hallway lit.

T____________T
01234567890123   

You can expand this to two dimensions by placing a second line of torches 7 to one side and offset by seven.

T____________T______
____________________
____________________
____________________
____________________
____________________
______T____________T

See this post

Answer 3

Mobs will spawn in areas of light 7 or lower. Source

Torches provide a light of 14, with the light value being reduced by 1 for every tile away.

14     13     12     11     10     9     8     9     10     11     12     13     14

Consider the line of light values above. The 14's are torches. If you put the torches no more than 11 squares away, you will prevent any monster from spawning; do note however, that if you go with a strictly grid based system, you will have dark "centers" made from the torch squares. I recommend a staggered grid, so that the light values prevent the centers from getting to dark.

Answer 4

First, some mob spawning science:

• Spawns occur in a 144x144 square around you (assuming a perfectly flat surface), but not within a 24 block radius of you.
• Hostile mobs spawn at light = 7 or less
• A torch provides 14 light to adjacent blocks and one less light per block of distance.

Using these measurements, it looks like you would have to make a grid of torches 13 squares apart that covers a 144x144 block area (excepting the no spawn circle around you, if you like).