Image to ASCII Art Converter

About Image to ASCII Art Converter

Turning an image into ASCII art means cutting it into a grid, measuring the average brightness of each cell, and placing a character whose ink coverage matches that brightness. Here you choose the number of columns (20 to 300, up to 2,400 in ultra mode), the tool works out the rows, and you can switch character sets, inversion, gamma, auto contrast and color before copying the text or saving a TXT or PNG.

Three things decide whether the result looks good: which characters you use and in what order (the brightness ramp), how you correct for character cells not being square (aspect ratio), and whether the image's brightness range actually uses the whole ramp.

The brightness ramp

The default ten-step ramp is " .:-=+*#%@". A space leaves the cell almost entirely paper; @ fills a large share of it with ink. The 70-step ramp is Paul Bourke's 1997 list reversed to run light to dark. More steps give smoother gradients, but the characters have very different shapes, so at small sizes the texture can look noisy rather than smooth.

Ink coverage depends on the font. The same # covers a different area in Consolas, Menlo and Courier New, so any ramp is only an approximate ordering. The block ramp (░▒▓█) has well-defined fill ratios and a stable order, but some fonts, especially CJK ones, draw these glyphs at double width. The tool's PNG export uses a Latin monospace font stack and squeezes each glyph into its cell, so the grid holds there; a TXT file uses whatever font the viewer picks, so it can still break in an editor that defaults to a CJK font.

The default mapping assumes dark text on a light background: bright cells get a space, dark cells get @. If you are pasting into a terminal with a black background, turn on Invert, or you will get what looks like a photographic negative.

Character cells are tall: aspect correction

A monospace character cell is typically about 1.8 to 2 times taller than it is wide. Sample the image on a square grid and put one character per sample, and the result is stretched vertically by that factor. The tool therefore computes rows as columns × (image height / width) × character aspect ratio. The default is 0.55, adjustable from 0.3 to 1.

If the output looks squashed or stretched, set this value to match the font where the art will be displayed. Editors and web pages with generous line-height make each row taller still, so lower the value for those.

How a cell's brightness is measured

Each cell is summarized by the average color of all pixels in its block rather than a single sample point, which keeps fine texture from turning into random speckle. Transparent pixels count in proportion to their alpha, and a fully transparent cell is treated as white. That is why the empty area around a transparent PNG logo does not fill up with @.

Brightness is the weighted sum 0.2126 R + 0.7152 G + 0.0722 B, the Rec. 709 luma weights, applied to the gamma-encoded values without linearizing. For picking characters only the ordering matters, so this shortcut is harmless. Hazy photos bunch their brightness in the middle and never reach either end of the ramp; auto contrast trims the darkest and lightest 2% and stretches the rest to 0 to 255. Gamma above 1 darkens midtones, below 1 lightens them.

Choosing a column count

Classic terminals are 80 columns wide, which is also a sensible limit for README files and code comments. Around 120 columns is enough for a recognizable face. Past 200 the output starts reading as a halftone photo rather than as text art, and ultra mode, which spends several characters per source pixel, is meant for large rendered PNGs rather than pasting.

Worked examples

How to use it

1. Drop or choose an image.
2. Pick the column count and character set; turn on Invert for dark backgrounds.
3. Fix proportions with the character aspect ratio, and flat images with auto contrast or gamma.
4. Copy the text or save it as TXT or PNG.

Frequently asked questions