A Minecraft igloo build is a hollow dome of snow blocks with a low tunnel for a door. At 11 blocks wide, the smallest size that reads as a dome, the shell is 189 snow blocks, which is 756 snowballs, and it stands 6 blocks tall. For scale, the igloo the game generates on its own is 94 snow blocks and 2 ice in Java Edition, according to the Minecraft Wiki. That puts it between a 7-wide and a 9-wide dome.
Table of contents
Open Table of contents
Igloo sizes and snow block counts
These are hollow shells one block thick, counted with the same algorithm the dome generator runs. The floor is not included, because an igloo sits on whatever ground is already there.
| Width | Height | Snow blocks | Stacks | Snowballs | Floor inside |
|---|---|---|---|---|---|
| 7 | 4 | 57 | 57 | 228 | 21 |
| 9 | 5 | 121 | 1×64 + 57 | 484 | 37 |
| 11 | 6 | 189 | 2×64 + 61 | 756 | 69 |
| 13 | 7 | 245 | 3×64 + 53 | 980 | 97 |
| 15 | 8 | 321 | 5×64 + 1 | 1,284 | 137 |
| 17 | 9 | 405 | 6×64 + 21 | 1,620 | 177 |
A 13-wide igloo is 245 snow blocks, or 980 snowballs, and 7 blocks tall. A 9-wide igloo is 121 snow blocks and 5 blocks tall. Every size is half its width tall, rounded up. Past 17 wide the build stops being an igloo and turns into a hall, and the dome block count tables carry on from there up to 63.
The Floor inside column is the open ground within the bottom ring. It is there for carpet, which is what the generated igloo uses.
Which size suits an igloo build
Seven wide is the closest to the vanilla igloo in cost, and it is a hut. Its four layers are 16, 16, 16 and 9 blocks: two identical rings, then a 5 by 5 square frame, then a 3 by 3 lid. Nothing in it curves.
Nine wide has five layers of 32, 24, 24, 28 and 13 blocks. Every ring differs from the one under it, but the roof comes to a 5-wide diamond and the whole build is only five steps from ground to top. Eleven is where I would start: six layers, a rounded 21-block cap, and enough steps for the outline to read as a curve. That agrees with the line the dome tutorial on this site draws, that a dome under about 11 blocks across comes out as stacked steps. Thirteen adds a straight wall two rings high before the curve begins, which makes it the easiest of the small sizes to furnish.
Headroom is the other half of the choice. Standing takes two blocks of air. The centre of the room is 3 blocks high in a 7-wide igloo, 4 at 9 wide, 5 at 11 and 6 at 13. In the 11-wide igloo, 61 of the 69 floor blocks have standing room; the other 8 sit under the shoulders, where the second ring steps in over the floor. At every other width in the table you can stand on all of the floor.
The 11-wide igloo, layer by layer
# is a snow block. Layer 1 sits on the ground and layer 6 is the roof; the number after each label is the block count for that layer.
1: 28 2: 36 3: 40
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4: 32 5: 32 6: 21
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........... ........... ...........From the ground up the six layers are 28, 36, 40, 32, 32 and 21 blocks, 189 in all. The third layer is the largest even though it is no wider than the base. The wall leans in there, so the ring doubles up at its corners to stay resting on the ring below.
The dome generator shows the same six layers one at a time. Set Diameter to 11, keep Fill Mode on Hollow and step the Shape Layer slider; the Materials panel gives the count for the current layer, so each ring can be matched to the numbers above. MC Shapes is a free, browser-based set of Minecraft shape generators (circle, oval, sphere and dome) that outputs block-by-block blueprints with exact block counts; it does not export schematic files. For the building order itself, base ring first and a count check on every ring, the dome tutorial is the method I would follow.
The entrance tunnel
A doorway 3 wide and 2 tall, cut on one of the four axes, removes 6 snow blocks at every width in the table. The first two rings run flat across at least three blocks there, so the cut is clean.
The tunnel in front of it is the top half of a 5-block circle: 7 snow blocks for every block of length, with a passage 3 wide and 2 tall inside. It is the same rule as any round arch over a 3-wide opening. A tunnel three blocks long is 21 snow blocks, which brings an 11-wide igloo to 204 with the doorway taken out.
On the 11-wide igloo the tunnel meets the wall without any patching. The front of that dome is already 5 blocks wide on its first two rings and 3 wide on the third, which is the outline of the tunnel arch. I have not checked the other widths for the same fit, so expect to fill a corner or two on those.
Snow, ice and light
Light the inside however you like. The wiki states that snow blocks, unlike snow layers, do not melt next to a light-emitting block, so the shell itself is never at risk.
Ice windows are where igloos get ruined. The generated igloo has two of them, and the wiki’s rule is that ice melts when the block light next to it is above 11; sunlight does not count. A torch gives off light level 14 and block light drops by one for each block of distance, so a torch has to sit at least four blocks away from an ice window, and a lantern, at 15, at least five. Soul torches and soul lanterns are level 10 and a redstone torch is 7, and none of those can melt ice at any distance. The generated igloo is lit by a single redstone torch, presumably for that reason.
Packed ice does not melt, but the wiki lists it as opaque, so it works as a wall block and not as a window. Glass is the transparent block that never melts.
Gathering the snow in survival
Every snow block is 4 snowballs, and a snow block broken with a shovel that lacks Silk Touch drops those 4 snowballs back, so nothing is lost moving between the two. Snow layers give one snowball per layer, also with a shovel. Without a shovel you get nothing from either.
What runs out first is inventory space. Snowballs stack to 16, which makes the 756 snowballs of an 11-wide igloo 47 stacks and 4, more than the 36 slots a player has. As snow blocks the same material is 2 stacks and 61. Craft as you dig. How long the shovelling takes depends on how deep the snow lies where you are, and I have no number for it.
What stays hand work
The dome generator draws the shell and stops there. The doorway, the tunnel, the windows and anything on the floor are cut and placed by hand, and the blueprint is full blocks only, so a skin of snow layers to soften the steps is yours to work out.
A little over three stacks of snow blocks cover the 11-wide igloo build with its tunnel, 204 in all. For any other width, the dome generator has the snow block total, the height and every ring on screen once Diameter is set and Fill Mode is on Hollow.