Online ASTC Converter & Encoder - Convert PNG/JPG to ASTC Textures
Convert PNG, JPG, and WebP images to ASTC compressed textures online. Configure 14 standard 2D block footprints (4×4 to 12×12) or 3D slice modes with quality presets in your browser using private WebAssembly encoding.
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Step 1: Select Image
Drag and drop an image here
or
- Supported formats: PNG, JPG, WebP
- All block sizes supported, choose based on quality/size trade-off
HDR input note
HDR, EXR, and UltraHDR JPEG files can be used as inputs. Most current output paths still tone map into the RGBA8 encode pipeline; use DDS BC6H, KTX2 RGBA16F, or KTX2 RGBA32F when you need to preserve HDR source data as much as possible.
Key Features
100% Browser-Based
All encoding happens in your browser. No server upload, complete privacy.
14 Standard 2D Block Footprints (4×4 to 12×12)
Full support for all 14 standard 2D block footprints from 4×4 to 12×12, with dedicated 3D slice compression modes.
Quality Control
Select encoding quality from fast to exhaustive for the perfect speed/quality trade-off.
Instant Preview
See your image preview in real-time before encoding to ASTC format.
Fast WebAssembly Compression
High-performance WebAssembly compression generates standard .astc textures locally. Verify your target engine (e.g. Unity, Unreal, or custom pipelines) supports raw .astc container imports.
Free & Open
No registration, no limits, no hidden costs. Use it freely.
How to Use ASTC Encoder
Upload Your Image
Drag and drop a PNG, JPG, or WebP image. The encoder supports arbitrary non-power-of-two (NPOT) 2D images, as well as vertical slice atlases for 3D textures.
Choose Block Size & Quality
Select from 14 standard 2D block footprints (e.g. 4×4 or 5×5 for normal maps, 6×6 or 8×8 for albedo, up to 12×12 for maximum compression) or 3D mode, and configure the encoding quality preset.
Encode with WebAssembly
The in-browser WebAssembly encoder compresses your image into a standard .astc texture with status feedback and compression statistics.
Download ASTC File
Download the compressed .astc file. Ensure your target game engine or pipeline (such as Unity, Unreal Engine, or custom Vulkan/OpenGL ES loaders) supports importing raw .astc texture files.
Frequently Asked Questions
Yes. You can use this ASTC converter to encode PNG, JPG, WebP and other common image formats into .astc texture files directly in the browser without server uploads.
For mobile game textures: tangent-space normal maps and fine PBR textures typically use 2D 4×4 (8.00 bpp) or 5×5 (5.12 bpp); diffuse/albedo textures often use 6×6 (3.56 bpp); environmental terrain uses 8×8 (2.00 bpp); and 10×10 or 12×12 (0.89 bpp) provide drastic package slimming for skyboxes or distant geometry. For 3D volumetric textures, block depths are configured separately.
Yes! ASTC natively supports alpha channels with all block sizes, making it perfect for UI elements and transparent textures.
ASTC is the universal standard across mobile platforms: native on iOS (Apple Metal, A8+), Android devices (ARM Mali, Qualcomm Adreno, PowerVR GPUs), and graphics APIs including Vulkan and OpenGL ES 3.2+. GPU hardware decodes textures directly in VRAM.
This tool encodes standard single-surface .astc files containing the primary image level. Automatic mipmap pyramid generation is not included in .astc encoding; mipmaps should be built in your asset pipeline or game engine.
No! All encoding happens entirely in your browser using WebAssembly. Your images never leave your device.