I'm trying to build a house out of ice, for no other reason than sheer novelty. (Though perhaps also because I want to use my Silktouch I pickaxe)

Ice is a very finicky building material, prone to melting when exposed to the "normal" light levels of a torch. Specifically, if any adjacent block attains a light level of 12 from anything other than direct sunlight, it will melt.

And so, I reach a conundrum. I want to light my house enough so that I can see while walking through it, and also enough to completely prevent mobs from spawning inside my house. This means I want to keep the light level approximately between 8 and 11: easy enough to do someplaces, but a pain in the butt to calculate for every potential spawnable square.

Is there some way to identify the light level of a block without the tediousness of manually calculating each block's light level? I'd prefer an external tool over a mod, but I'm willing to consider the latter anyway.

  • @ChrisF the issue is not how to calculate light level. I know how to do that. The issue is needing to calculate the light level on each of the hundreds of square meters that compose my ice palace. Oct 26, 2011 at 22:06
  • 2
    I didn't realise the extent of the problem :)
    – ChrisF
    Oct 26, 2011 at 22:06
  • Try turning off smooth lighting - it may be much easier to get a "feel" for how each light level looks like visually with the flat lighting view.
    – Random832
    Oct 27, 2011 at 16:26
  • I think you should try Red stone torches if not that then try glow stone. (glow stone is best) Oct 28, 2011 at 21:26

4 Answers 4


Press F3, and look for the area labeled bl: When you find this it will tell you the artificial (not natural) light of the block you're standing on.

  • awesome updated answer that deserves more upvotes
    – legacy
    Jun 26, 2013 at 20:57
  • like benokt said the block lighting level will appear like this: bl:[light level] it will also appear by the biome display text like this: lc:[#] b:[biome] bl:[light level] 2nd to last line from the bottom
    – user52491
    Jul 24, 2013 at 15:19

Your best bet would be to open up your favorite skin, find the lighting file -- like this one -- and modify it in your favorite image editor so that the lighting levels above/below/inside your desired range are made obvious (red, green, and white may be good choices). Be sure to disable smooth lighting while you do this, though.

  • Oooh, this looks promising. Oct 29, 2011 at 1:27
  • Hm. I can't seem to make this noticeable. I don't know if I'm just doing it wrong or what. Oct 29, 2011 at 2:36
  • Are you sure it's set up properly? If you make it something obvious like all red, then it should be pretty obvious if it's working or not. I'll take a look at it in a few hours and see if I can figure out the problem.
    – Xkeeper
    Oct 31, 2011 at 23:33
  • 2
    if you get it working, see if you can upload it as a texture pack somwhere! Oct 31, 2011 at 23:39

Use the What's My Light Level? mod, compatible up to 1.9 pre-4 (unstable) and 1.8.1 (stable).

This mod provides an overlay that shows the light level of the block you are standing on.

enter image description here

  • Neat! I'm trying to avoid mods though, because I'd like to build my ice palace on a multiplayer server. Still quite helpful for those building in single player, however. Oct 26, 2011 at 22:13
  • @RavenDreamer I think you may find that difficult (I'm not sure if there are any 'live updating' external programs, unlike mappers). My advice: build a small ice palacette in single player, until you've got the hang of where to put lights to prevent meltage, then go multiplayer when you've got enough practice.
    – fredley
    Oct 26, 2011 at 22:16
  • Yeah, I wasn't looking for a live-updating program, just something that would let me iterate. Save map, view changes in external program, make changes as necessary, close map, reopen map,e tc. Oct 26, 2011 at 22:18
  • 9
    @Raven Dreamer — Not all mods require a server-side component. I've used Zombe's "safety" mod (another light-level indicator) in SMP on a vanilla server. I would imagine this one is SMP-compatible as well.
    – Ben Blank
    Oct 26, 2011 at 22:49
  • Oh, wow, this was really easy to install. Nice. If Xkeeper can't get their texture pack idea working, I'll accept this. In the meantime... upvoats! Nov 1, 2011 at 1:58

I recently had a similar task and couldn't find an external tool/helper so I made a LibreOffice Calc document.

It's basically just a formula{1} in sheet "LL" which looks in all four directly adjacent cells for a light level above a certain threshold and outputs that level minus one (or zero if below the threshold).

It takes height levels from sheet "HM" into account as well but there are caveats.

See linked WP-post for more details.

{1} eg. in cell C2: =IF(MAX(C1-($HM.C1-$HM.C2); B2-($HM.B2-$HM.C2); D2-($HM.D2-$HM.C2); C3-($HM.C3-$HM.C2))>$A$1; MAX(C1-($HM.C1-$HM.C2); B2-($HM.B2-$HM.C2); D2-($HM.D2-$HM.C2); C3-($HM.C3-$HM.C2))-1; 0)

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