Debug screen

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This feature is exclusive to Java Edition.
Screenshot showing the debug information

The debug screen is triggered when the F3 key is pressed. 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.

Legend[edit]

When displaying reduced debug info, only the starred items are included.

Name Description[1][2]
fps* The frame rate (also known as frame frequency) is the frequency rate at which a video device produces unique consecutive images called frames. Frames are still pictures that when sequenced together form a fluid animation that is the basis for all moving media. Frame rate is most often expressed in frames per second (fps).
chunk updates* [until 1.15] Chunk updates are the number of 1-block spaces which have changed its state or content in the last second. This change in state can be caused by the addition or subtraction of blocks from the map, sugarcane or bamboo growing, water or lava flowing, redstone contraptions, loading/unloading chunks, and more. Chunk updates are usually high right after map generation.
integrated server* The time it takes for a tick on the integrated server, number of packets sent by the client (tx), and number of packets received by the client (rx).
C* Number of chunk sections rendered over total number of chunk sections in the loaded area.
D* Client-side render distance.
L Client-side blocks count that have light update to apply.
pC* Pending chunks to be batched.
pU* Pending uploads to video card.
aB* Available buffers to use in the batching process.
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* 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* Shows the max framerate ("inf" if Unlimited) and the Graphics type ("fast" if Fast and none if Fancy), including cloud settings ("fast-clouds" if Fast, "fancy-clouds" if Fancy and none if clouds are off).
All* Displays total number of loaded entities (including mobs and dropped items).
MultiplayerChunkCache* The most chunks that will be loaded.
Dimension FC The current dimension of the player with the count of force loaded chunks (FC = Forceloaded Chunk). Shows n/a if no chunk in this dimension is forceloaded.
XYZ X: Player's location in blocks East of 0,0 (negative values are to the West).

Y: Player's (feet) altitude in blocks (63 is overworld sea level, 11 is overworld lava flood level, 32 is nether lava sea).
Z: Player's location in blocks South of 0,0 (negative values are to the North).

Block The coordinates of the block the player's feet are in, in xyz format. Very similar to XYZ as above, rounded to the nearest whole number.
Chunk* The location of the player within a chunk, and the location of the chunk within the world. In reduced mode, only the location within the chunk is displayed.
Facing The direction in which a player is facing. Towards Positive X/Z indicates the player's alignment towards the x/z axis. The two numbers at the end indicate the player's horizontal (azimuthal) and vertical (altitudinal) rotation.
Client Light The client-side light values, where a is the sky light level and b is the block light level.

The first number is the total light level where the player's feet are. Note that there are a few caveats here due to the sky light level showing 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.
The second number is the amount of light from the sky at the block the player's feet are in. Same caveat as above.
The third number is the amount of light from other blocks (e.g. torches) at the block the player's feet are in.

Server Light The server-side light values.

Exactly the same as the described in Client Light, but the first number "total light level" doesn't exist.

CH / SH Describes the Y coordinate of highest block that exists at the player's current X/Z coordinates.

CH: client-side values

S: The Y coordinate of the highest block at this X/Z coordinate.
M: The Y coordinate of the highest block at this X/Z coordinate that has a solid bounding box. Blocks like flowers or torches are ignored.

SH: server-side values

S: The Y coordinate of the highest block at this X/Z coordinate.
O: The Y coordinate of the highest block at this X/Z coordinate that has a solid bounding box and is not a liquid.
M: The Y coordinate of the highest block at this X/Z coordinate that has a solid bounding box. Blocks like flowers or torches are ignored.
ML: The Y coordinate of the highest block at this X/Z coordinate that has a solid bounding box and is not leaves.
Biome Shows the player what biome they are in. If the Y is below 0 or above 255, the words "Outside of world…" are shown instead.
Local Difficulty Shows the difficulty of the chunk the player is in. See Difficulty on how this works. The second number displays the number of in-game days the player has been in the world, see Day-night cycle for more information.
Sounds Represented by: Number of sounds playing/maximum of sounds playing.

The first pair represents sounds as breaking or placing a block, moving or burning fire.
The second pair represents ambient (and loop[verify]) sounds.

Looking at Shows the coordinates of the block the player is looking at. If the player is not looking at any block, this entry does not appear.

Profiler graph[edit]

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.

Frame time graph[edit]

Bar chart in the lower left of the Alt+F3 debug screen displays real time measurement of seconds per frame with lines marking 160 and 130 seconds per frame. The graph is color coded from green to yellow to red, with green being faster frame time, red being slower frame time, and yellow in between.

Screenshot of the frame time graph re-introduced in Java Edition 1.8.2-pre1, taken by TheMogMiner.

More debug-keys[edit]

Text will be shown in chat for most debug keys listed here. Note that when using a specific key combination like F3+N, F3+B, etc., the debug screen will not open.

  • F3+A : Reload all chunks.
  • F3+B : Toggle visibility of hitboxes of visible entities. It also shows which direction entities are looking, as well as the entities eye level.
  • F3+C : Copies the player's coordinates and rotation in the form of a /tp command.
    • Holding for 10 seconds instead forces a debug crash.
    • Ctrl+F3+C forces a Java crash instead of a regular Minecraft crash. However, with some keyboards, it only triggers with right control, thus using left control will produce a regular crash.[3]
Screenshot of the crash alert given in the chat while holding F3+C.
  • F3+D : Clear chat history (including previously typed messages and commands) (As of Java Edition 1.11, players can still use the up button to view previous commands/things they said in chat).
  • F3+F : Increases render distance by 1 (must be between 2 and 32).
  • F3+⇧ Shift+F : Decreases render distance by 1 (must be between 2 and 32).
  • F3+G : Toggles the visible chunk borders around the player.
  • F3+H : Toggle visibility IDs of items, durability of tools, armor color. and the scale of maps when such items in an inventory.
  • F3+I : Copies block or entity data to the clipboard.
  • F3+N : Cycle between Creative and Spectator gamemodes.
  • F3+P : Toggle automatic pause when Minecraft loses focus on / off.
  • F3+Q : Gives help and shows all F3 + key combinations.
  • F3+T : Reload textures, models, sounds, and any other resource pack contents.
  • F3+Esc : Toggle pause without pause menu (if pausing is possible).
  • ⇧ Shift+F3 : Opens the debug screen with the profiler graph.
  • Alt+F3 : Opens the debug screen with the Frame time graph.
  • (note that both graphs can be opened with ⇧ Shift+Alt+F3)

When the reducedDebugInfo gamerule is set to true, the effects of F3+B (entity hitboxes), F3+G (chunk boundaries), F3+C (copying coordinates), and F3+I (copying block/entity data) will not be shown. Holding down F3+C to initiate a crash will still work as expected, as well as Ctrl+F3+C

History[edit]

The debug information from Indev, Infdev, and early Alpha.
Java Edition Classic
0.0.2aThe version number is now displayed in the top-left corner.
0.0.9aAdd the debug screen.
The debug screen includes the fps, and chunk updates.[verify]
Java Edition Indev
?Added an option to turn on the debug screen. The current version name is always displayed even when the option is disabled.
Java Edition Alpha
v1.1.0The debug screen is no longer listed as an option and now requires F3 to be held down to activate.
v1.2.3The coordinates have now been added to the debug screen.
Java Edition Beta
1.3The debug screen, along with other function key controls, has now become a toggle.
When the debug screen is open, it will now show numbers above every mob; these numbers being the mob's Entity ID. These numbers are visible through blocks, making F3 a very useful mob-finder.
1.7The "f" coordinate has now been made visible in the debug screen (facing direction).
1.8?The ability to see the level's seed has now been added to the debug screen.
Entity numbers being shown above a mob's head have now been removed from the debug screen. Some players felt that it was cheating and that it took away from the game.
Java Edition
1.0.0October 2, 2011The first images of a runtime performance profiler with a pie chart is revealed.
?The profiler has now been added to the debug screen.
1.2.11.2-preInformation about the biome and light level of the player's location have now been added to the debug screen.
The seed in multiplayer has now been made hidden from the debug screen and now shows as "0".
1.2.4Pressing 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).
1.3.112w18aInformation about the player's speed and whether the player is touching the ground have added to the debug screen.
Coordinates within the debug screen are now rounded to 5 digits.
12w21aInformation about the world's seed has now been removed from the debug screen, seen instead by pressing the chat key and typing /seed.
The frame time graph has now been removed from the debug screen.
1.4.212w39aFl, x and z chunk coordinates, and more rotation (f) information have now been added to the debug screen.
12w41aShift+F3 now shows the profiler graph in the debug screen.
1.814w02aThe debug screen now shows which axis the player is facing after the cardinal direction: "Towards positive/negative X/Z".
14w04aThe crosshair in the debug screen will now display 3 short colored lines to indicate the direction of each axis: x/red, y/green, z/blue.
The x coordinate line in the debug screen will now be bold when looking east/west, similarly the z coordinate line will now be bold when looking south/north.
14w05aText within the debug screen now has a background.
X, y, z, b, bl and other labels within the debug screen have now been replaced with more understandable labels.
"Light" is now the light levels at feet, not eyes.
14w06aX, Y, and Z title in the debug screen has now been changed from 'Feet' in the previous snapshot, to 'XYZ'.
A day counter, which increases by 1 every dawn, has now been added to the debug screen.
The debug screen now displays difficulty: Peaceful- 0.00, Easy- 0.75, Normal- 1.50, Hard 2.25 (but numbers slowly increase the longer the player is in an area).
The debug screen now displays player rotation in degrees and quadrants.
14w11aOn the right-hand side of the debug screen, a display shows up if the player is looking at a block, showing its ID and block states.
14w17aAll blocks now have their info displayed on the right-hand side of the F3 debug screen.
The "Facing negative/positive x/z" from the debug screen has now been removed.
14w20aThe "Facing negative/positive x/z" has now been readded to the debug screen.
14w25bF3 + B now also shows which direction entities are looking in using a blue line.
The line on the right-hand side which had displayed the name of the block model the player was looking at has now been removed from the debug screen.
14w29aA 'Reduced Debug Info' toggle now exists within multiplayer settings to enable/disable reduced information on the debug screen.
The reducedDebugInfo gamerule allows the player to enable/disable reduced information on the debug screen. This overrides all 'reduced debug info' settings in clients.
14w30aThe debug screen now displays how many chunk sections are being rendered currently and how many chunk sections are out of view in percent, the OpenGL version, display size, vendor and GPU.
"Vanilla" has now been added to the version number within the debug screen.
1.8.2pre1The frame time graph within the debug screen has now been readded and redesigned, so that it can now be activated using Alt + F3.
1.915w32aF3+N now toggles between creative and spectator mode, when the player is in either of them. The player needs to be allowed to use /gamemode for this to work.
15w43aThe debug screen now shows more information.
F3+Q gives help and shows all F3 + key combinations.
F3+F now increases render distance by 1 (Minimum and Maximum are 2-32).
F3+⇧ Shift+F now decreases render distance by 1 (Min and Max are 2-32).
The debug screen now shows if the pie chart and fps chart are shown on screen.
The debug screen now shows text in chat when the player reloads chunks, sounds, etc.
The debug screen now does not open when the player uses a specific key combination like F3+N, F3+B, etc.
F3+S has now been removed from the debug screen, which previously reloaded sounds.
F3+T now reloads all resource pack content, including sounds.
Red, blue and green lines have now changed in size within the debug screen and now change relative to the GUI scale.
1.1016w20aF3+G toggles the visible chunk borders around the player.
The 3 lines indicating direction now have a small black outline when looking at an area with bad contrast.
1.1318w11aPressing F3+C now copies the player's current location to the clipboard in the form of a /tp command, though holding for 10 seconds and releasing will still force a debug crash.
18w14aThe debug screen now gives a warning before forcing a debug crash.
18w22cF3 debug overlay now shows the fluid the player is looking at, separately from blocks.
pre6F3+I copies block or entity data to the clipboard.
Added information about the time it takes for a tick on the integrated server, number of packets sent by the client (tx), and number of packets received by the client (rx).
pre7Added "Looking at liquid" row, which displays the targeted fluid's coordinates.
"Looking at" row within the debug screen has now been renamed to "Looking at block."
"Targeted Block" information now targets through fluids. It will display information for blocks up to 16 blocks away.
Added "Targeted Entity," which displays information for entities up to 16 blocks away.
F3+I[note 1] has now been changed to now be ⇧ Shift+F3+I. It is now clarified that it copies the client-side data of targeted block or entity. It still can be used by anyone.
Added F3+I to copy targeted block or entity server-side data to clipboard. It can only be used by operators.
1.13.118w30aAdded Ctrl+F3+C to force a JVM crash, instead of a regular crash.
18w31aAdded new fields for the current dimension and the related force loaded chunks.
1.1418w43cPressing Alt+F3 now shows TPS (ticks per second).
Added min/avg/max tick times to help find stutters.
1.14.1Pre-Release 1Pressing F3+Esc now toggles pause without pause menu (if pausing is possible).

Pre-1.8 legend[edit]

Name Description[4][5]
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 render passes.
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 Displays the player's max framerate
ALL Displays total number of loaded entities (including mobs and 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 the player's chunk number with the block within the chunk in ()
y Player's altitude in blocks (63 (62.9) is overworld sea level, 11 (10.9) is overworld lava flood level, 32 (31.9) is nether lava sea).
z Player's location in blocks South of 0,0 (negative values are to the North) and after the // is the player's 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) and if the player walks towards x or z respectively
lc Max section height for the chunk the player is in (uses cubic chunk sections, so heights will display in multiples of 16 minus 1).
b Shows the player what biome they are in.
bl (for "block light") The amount of light from other blocks (e.g. torches) at the block the player's head is in. If the player stands on top of a torch, this field will show a light level of 13 instead of the expected 14, due to the player's head being one block away from it.
sl (for sky light) The amount of light from the sky at the block the player's 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 the player's 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 able to stand, rounded up when standing on half-blocks, such as slabs. When above the void (where there is no block), it will say 0.
shader The file path of the currently-active shader (within the "assets" directory of minecraft.jar). Only displayed if a shader is active.

Trivia[edit]

  • Lc, Biome, and the lighting values do not display when the player are in the void or above y = 255 (in the Overworld)
  • When used in a chunk that was created prior to Alpha 1.2 (when there were no biomes), the B field will read "Ocean".
  • Deeper into the profiler (⇧ Shift+F3), some tasks will have numbers higher than 9 and can't be accessed. Pressing the two keys simultaneously will not open the task.

Issues[edit]

Issues relating to "Debug screen" or "F3" are maintained on the bug tracker. Report issues there.

Gallery[edit]

Notes[edit]

  1. F3+I was used to copy targeted block or entity data to clipboard.

References[edit]