Online ASTC Converter - Convert PNG/JPG to ASTC Format Free
Quickly convert your PNG and JPG assets to ASTC compression for mobile use. Flexible online ASTC encoder running securely in browser.
Related Resources
Step 1: Select Image
- 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 Block Size Options
Choose from 4×4 to 12×12 block sizes for optimal quality/size balance.
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 Encoding
WebAssembly-powered compression delivers near-native performance in your browser.
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. ASTC supports any dimension, no restrictions on multiples.
Choose Block Size
Select block size based on your needs: 4×4 for highest quality, 12×12 for maximum compression.
Encode
The tool automatically encodes your image to ASTC format. Progress is shown in real-time.
Download ASTC File
Download the compressed ASTC file and use it in your game engine or OpenGL/Vulkan application.
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.
Smaller blocks (4×4, 5×4) provide higher quality but larger files. Larger blocks (10×10, 12×12) give better compression but lower quality. 6×6 or 8×8 are good balanced choices.
Yes! ASTC natively supports alpha channels with all block sizes, making it perfect for UI elements and transparent textures.
ASTC is supported on iOS (A8+), modern Android devices, and desktop platforms with OpenGL ES 3.2+ or Vulkan 1.0+ support.
ASTC generally provides better quality than ETC2 at similar bit rates, with more flexible compression options through variable block sizes.
No! All encoding happens entirely in your browser using WebAssembly. Your images never leave your device.