Debug Screen

Screenshot showing the debug information

File:DebugScreenAlpha.png

The debug information from Indev, Infdev, and early Alpha.

The debug screen is triggered when the F3 key is pressed (Fn+F3 on Macs [by default; the behavior of the F keys can be changed in Keyboard preferences] and some laptops). It shows the chunk cache, the memory usage, various parameters, the player's map coordinates and a graph that measures the game's current frame rate. It can be very useful for telling other players your map location and monitoring performance. As of 1.2.4, pressing F3 (Fn+F3 on Mac and some laptops) brings up the debug screen but without the graphs. The graph will appear on pressing ⇧ Shift+ F3 (Fn+ ⇧ Shift + F3 on Mac and some laptops). As of 1.3.1, seed is only available by hitting the chat key and typing "/seed".

Legend

Name	Description<ref>http://gaming.stackexchange.com/questions/14990/minecraft-debug-screen</ref><ref>http://www.minecraftforum.net/viewtopic.php?f=35&t=13231</ref>
C	Number of chunk sections rendered over total number of chunks. Counts all render passes: if a chunk section is rendered twice (because it contains both water and normal blocks, for example) then it will be counted twice.
F	Number of chunk sections loaded outside the viewing distance. Counts all render passes.
O	Number of chunk sections removed through occlusion culling. Counts all render passes.
E (first row)	Number of empty chunk sections. These sections are skipped for one of two reasons: Either the chunk has not yet been loaded and rendered into polygons, or the section has nothing to draw in the current render pass. Counts all renderpasses.
E (second row)	Number of rendered entities over total entities
B	Unused, always 0. May previously have been the number of entities removed due to hidden chunks
I	Number of invisible entities
P	Number of particles on screen
T	Unknown. Currently displays "All:" followed by the number of loaded entities (includes mobs as well as dropped items).
ServerChunkCache ChunkCache	The most chunks that will be loaded
x	Player's location in blocks East of 0,0 (negative values are to the West) and after the // is your chunk number with the block within the chunk in ()
y	Player's altitude in blocks (63 (62 and 14/16th) is overworld sea level, 11 (10 and a large fraction) is overworld lava flood level, 31 is nether lava sea).
z	Player's location in blocks South of 0,0 (negative values are to the North) and after the // is your chunk number with the block within the chunk in ()
f	The direction in which a player is facing (south=0, west=1, north=2, east=3)
lc	Max section height for the chunk you are in (Uses cubic chunk sections, so heights will display in multiples of 16 minus 1.)
b	Shows you what Biome you are in.
bl	(for "block light") The amount of light from other blocks (e.g. torches) at the block your head is in. If you stand on top of a torch, this field will show a light level of 13 instead of the expected 14, due to your head being one block away from it.
sl	(for sky light) The amount of light from the sky at the block your head is in. Note that the number shown here is only accurate during the day. It shows the light level the block would get from the sun in full daylight, but does not account for the lower light levels at night or during a storm.
rl	(for raw light) The total light level where your head is, equal to max(bl,sl). Note that because the "sl" field is factored in here, this field has the same caveats as that one.
ws	Walking speed.
fs	Flying speed.
g	On ground, Boolean value, true if the player touches the ground.
fl	The y-coordinate of the highest block where the player is standing, rounded up when standing on half-blocks, such as Slabs.

Profiler graph

Pie charts in the lower right of the Shift+F3 debug screen display real time profiling information. More detailed information about one section can be displayed by using the keys 1-9. Press 0 to go back to the previous section.

More Debug-Keys

• F3 + A : Reloading all chunks
• F3 + B : Toggle Hitboxes of entities
• F3 + C : Make a Debug-Crash (press keys for 10 seconds) <ref>https://mojang.atlassian.net/browse/MC-942</ref>
• F3 + F : Toggle View distance between Far / Normal / Short / Tiny
• F3 + H : Toggle IDs of items, the durability of tools and the scale of maps
• F3 + P : Toggle Auto-Pause when Minecraft loses focus on / off
• F3 + T : Reload the Texture Pack, useful for developers of texture packages

Trivia

• Lc, Biome, and the lighting values do not display when you are in the void or above y = 255 (in the Overworld)

• When triggered in the nether, the "B" (biome) displays the biome of "Hell". In The End, it will indicate the biome "Sky", likely because The End was originally going to be the Sky Dimension.