Words or a picture
Words draws what you type in a pixel font made for this page: Classic is 5 dots by 7 for each capital letter, Tiny is 3 by 5. Pick a block for the letters and one for behind them, or leave the back empty. A picture takes a JPG, PNG, WebP, GIF (its first frame), HEIC or SVG. Pick how many blocks wide the art should be and the height follows the picture's shape, up to 320 blocks either way. The picture is read in this page and never uploaded.
How the blocks are chosen
Each block's colour here is its map colour: the single colour the game itself gives that block in its data, the one it draws on a map. No textures are used. For every square of the picture the page picks the block whose colour is nearest, measured in OKLab, a colour space where equal distances look like equal differences. That keeps skin tones and greys from turning green or purple the way plain RGB matching can. Fully see-through parts of a picture are left empty.
Dithering
With Dithering on, the difference between a square and the block chosen for it is passed on to the squares to its right and below (Floyd–Steinberg), so a smooth gradient comes out as a mix of two nearby blocks instead of hard bands. It suits photos. Leave it off for logos, sprites and text, where it only adds speckles.
Picking blocks
Tick the sets to draw from: Wool, Concrete, Terracotta and Other blocks (planks, stone, metal blocks and the rest). A colour that several blocks share uses the first one ticked; the menu beside it in the materials list swaps it for another block of the same colour. Leave out hard-to-get blocks drops things like diamond and emerald blocks, prismarine and silk-touch-only blocks. Leave out falling blocks drops sand, gravel and concrete powder, which fall out of an upright wall. Carpets, pressure plates and glass are never used, since pixel art is usually built standing up.
Reading the plan
Every square is one block. The lines every 16 blocks match the size of a chunk, so if you start the art on a chunk border (F3 + G shows them) each square of lines is one chunk. Point at a square, or tap it, to see the block and where it is: columns count from the left and rows from the top, with the row from the bottom as well for building upwards. The materials list counts every block, in stacks of 64 and shulker boxes of 27 stacks. Download PNG saves the plan with its list, to keep on a second screen.
Game data
Checked against Java Edition 26.2. The map colours have not changed since 1.17, when deepslate, raw ore blocks and glow lichen were added. Pixel art is built from blocks, so a plan works the same in Bedrock Edition, though a few block names differ there.
Questions
Why do the wool and concrete plans look the same?
Wool and concrete of one dye share a map colour in the game's data, so they match the same squares. In the game concrete is the brighter, flatter of the two; build a small test patch with each if the difference matters to you.
Can I use my own font or lowercase letters?
Not yet. Both fonts are capitals, numbers and common punctuation, drawn for this page; lowercase letters are written as capitals and a character a font has no shape for comes out as a question mark.
How big should I make it?
Wider shows more detail but takes more blocks: a square picture 64 blocks wide is 4,096 blocks, which is 64 stacks or about two and a half shulker boxes, and 128 wide takes four times that. Faces and logos read well from about 48 blocks; photos need 96 or more. Upright art is limited by the height of the world, 384 blocks from y −64 to y 319.
Are the colours exactly what I will see in the game?
Close, not exact. A block's real look comes from its texture and the light on it; the colour here is the one the game gives it for maps, which is a fair average. Lighting, shaders and resource packs all change what you see.
Is my picture uploaded?
No. It is decoded and matched in this page on your device, and nothing is kept once you close it.
What about map art?
Art meant to be seen on an in-game map follows different rules, with shading from block heights. The Map Art Planner plans that.