Pixel Art Upscaler

Pixel art is drawn at tiny sizes — 16 × 16 or 32 × 32 pixels — and ordinary resizing blurs it into mush. This upscaler enlarges it the way pixel artists expect: nearest neighbour turns every pixel into a crisp square at any whole factor from ×2 to ×32, while Scale2x, Scale3x and Scale4x round off staircase diagonals without adding new colours. Add grid lines to see the original pixels, for tutorials or cross-stitch charts. It runs in your browser.

How to use this tool

1. Choose one or more pixel art images (PNG or GIF keep exact colours).
2. Pick nearest neighbour and a factor, or Scale2x, Scale3x or Scale4x.
3. Optionally draw a grid between the original pixels (nearest, ×4 and up).
4. Download the enlarged PNGs.

Formula

nearest: output (x, y) = input (⌊x ÷ k⌋, ⌊y ÷ k⌋); Scale2x: if B ≠ H and D ≠ F, then E0 = D if D = B, E1 = F if B = F, E2 = D if D = H, E3 = F if H = F, otherwise E

In Scale2x each pixel E becomes a 2 × 2 block E0–E3, using its neighbours B (above), D (left), F (right) and H (below). The rules copy a neighbour into a corner only where two neighbours of the same colour meet, which smooths diagonal edges while keeping the palette. Scale3x uses all eight neighbours to fill a 3 × 3 block, and Scale4x applies Scale2x twice. Edge pixels repeat their own colour as missing neighbours.

Example

A 32 × 32 sprite at ×8 becomes 256 × 256 px with every original pixel an 8 × 8 square. With Scale2x a diagonal line of black pixels on white, one pixel thick, gets its outer corners filled in, so at 64 × 64 px it looks like a smooth slope instead of a staircase.