# FLUX 3 Image Klein, Explained

> Independent explainer for Black Forest Labs' FLUX 3 Image Klein open-weight image model. Not affiliated with Black Forest Labs. Updated 2026-10-17. Full page: https://lab.awaara.cn/flux-3-image-klein/

## What it is

FLUX 3 Image Klein is Black Forest Labs' open-weight image model, released October 15, 2026. It has 5.6 billion parameters and handles text-to-image generation, image editing and multi-reference generation from up to ten reference images, at up to native 4K resolution. Bounding boxes place elements or confine edits to one region.

The point of the release is size: the INT8 build runs on a GeForce RTX card with 8 GB of VRAM through ComfyUI or Diffusers. The release comes in two forms, a base model for fine-tuning and a step-distilled model for speed, with FP8, INT8 and NVFP4 builds developed with NVIDIA.

## Specs

- Released: October 15, 2026, by Black Forest Labs (Freiburg, Germany)
- Parameters: 5.6B; 38% fewer than FLUX.2 klein (9B)
- Capabilities: text-to-image, image editing, up to 10 reference images, native 4K, bounding-box placement
- Variants: base checkpoint (fine-tuning), step-distilled checkpoint (speed)
- Builds: BF16 (~11.2 GB weights, published), FP8 (~5.6 GB, published), INT8 (size not published; vendor-tested on 8 GB cards), NVFP4 (~2.8 GB estimated)
- Local speed: distilled INT8, ~4 s per 1MP image on RTX 5090, under 9 s on RTX 4070 (NVIDIA-measured, 16 steps)
- Frameworks: ComfyUI, Diffusers; LoRA training via Ostris AI Toolkit or NVIDIA NeMo AutoModel
- Hosted: BFL API (flux-3-image-klein), Playground, Hugging Face Spaces, OpenRouter
- API price: $0.009 per image at 1K, $0.036 at 4K
- License: FLUX Kommunity License — free commercial use under $5M annual revenue
- VRAM rule of thumb: BF16 needs a 16 GB card; FP8 fits 12 GB; INT8 fits 8 GB

## License

FLUX Kommunity License: free commercial use for individuals and businesses with annual revenue under $5M, plus research and non-commercial use. Above that line, use the hosted API or obtain a separate self-hosted license from BFL.

## Benchmarks (BFL-reported, from launch materials)

- Highest Elo among open models in BFL's internal testing
- +91 Elo points over FLUX.2 klein, with 38% fewer parameters
- BFL claims it beats closed models Ideogram V4.5 and its own FLUX.2 [pro] in its tests
- Independent runs had not landed by 2026-10-17.

## Access

- Weights: Hugging Face, GitHub; API: BFL API, Playground, Hugging Face Spaces, OpenRouter
- License: free to download; FLUX Kommunity License has a $5M revenue ceiling — read before commercial use