step 01
Add frames
Upload PNGs with transparency, or start from a built-in walk, idle, or VFX demo cycle so you can learn the packing rules immediately.
Sprite Sheet Lab · free
Pack frames into a game-ready sprite sheet
Uniform cells, bleed-safe padding, transparent PNG, and atlas JSON — the packing step engines need after you have animation frames, without fighting a graphics editor.
✓ Transparent PNG sheets✓ Atlas JSON metadata✓ Free · no credit spend
from frames to atlas
Upload frames, set the grid, export the sheet
step 02
Set the grid
Choose columns, frame size, and 1–2px padding — the same uniform layout Unity Multiple mode and Godot Hframes/Vframes expect.
step 03
Normalize cells
Every frame is fitted into an identical cell so baseline drift and mixed resolutions do not break engine slicing.
step 04
Export PNG + atlas
Download a transparent sprite sheet and JSON atlas with each frame's rectangle for custom importers and tooling.
where it fits
Who Sprite Sheet Lab is for
Character animation sets
Turn idle, walk, and attack frame dumps into one sheet per state before import into Unity, Godot, or Phaser.
VFX and UI bursts
Pack short impact, sparkle, or pickup sequences with consistent cell sizes and bleed-safe padding.
Jam-ready atlases
Stop hand-placing frames in a graphics editor when you only need a clean grid and metadata for the engine.
go deeper
Related reading and tools
sprite sheet faq
Questions, answered
What is bunpav's 2D sprite sheet generator?
Sprite Sheet Lab is a free browser tool that packs individual image frames into a uniform grid sprite sheet with configurable columns, frame size, padding, optional power-of-two canvas size, transparent PNG export, and JSON atlas metadata.
Does it generate AI artwork from a text prompt?
No. It packs frames you upload (or demo cycles you start from) into an engine-ready sheet. bunpav's planned bulk 2D AI generation is a separate roadmap feature; this tool solves the atlas packing and metadata step that engines actually need.
Why padding and uniform frame sizes?
Engines slice sheets by fixed cell size. Uneven frames cause offset loops, and zero padding often bleeds neighboring pixels when textures are filtered or scaled. Industry practice is 1–2px padding and identical cell dimensions across the sheet.
What do I export?
A transparent PNG sprite sheet plus a bunpav sprite-atlas JSON file listing each frame's x, y, width, and height. You still import and configure the sheet inside Unity, Godot, or your web engine.
Is Sprite Sheet Lab free?
Yes. Signed-in users can pack and download sheets without spending AI generation credits. Pair it with Sprite Animator when you want to preview the loop before import.