Model basics and release dates
FLUX 3 Klein (full name FLUX 3 Image Klein) is an image generation and editing model made by Black Forest Labs (BFL), the German company behind the FLUX model family. It pairs a 5.6-billion-parameter image model with a separate Qwen3-VL-4B text encoder and outputs images up to 4K resolution.
The model generates images from text prompts, edits images from instructions, combines up to 10 reference images, controls layout using bounding-box coordinates, and renders text inside images. The model card notes that it is meant to be used with a prompt upsampler (prompt expander), as short prompts used directly give mediocre results. You can find prompt ideas in the gallery or read how it relates to the earlier generation on the FLUX 3 Klein vs FLUX.2 Klein page.
The Hugging Face repository was created on October 13, 2026 (UTC). Black Forest Labs’ release notes and press coverage give October 15, 2026 as the release date.
Open weights and license
The model weights are open, but they are gated on Hugging Face. You must log into a Hugging Face account and accept the license terms before downloading the files. Step-by-step instructions are on the download guide.
FLUX 3 Klein uses the FLUX Kommunity License v1.0. According to the summary on the model card:
- Non-commercial use is allowed.
- Individuals and companies with annual revenue under US$5 million may run the model in production and use the generated images commercially.
- The license does not by itself allow commercial fine-tuning or redistribution of the model.
Because the full LICENSE.md file requires a login to view and was not reviewed by us, you must read the complete license yourself before relying on it. Note that using Black Forest Labs’ API is governed by BFL’s API terms, not the open-weight license. Read more on our license overview.
Hardware requirements and Mac status
Hardware needs depend on how you run the model:
- Black Forest Labs: BFL’s documentation lists an NVIDIA RTX 3090 as the minimum GPU.
- ComfyUI, INT8 version: ComfyUI’s documentation states that its INT8 version runs on GPUs with 8 GB of VRAM.
For local setup details, see our VRAM and hardware requirements and ComfyUI guide.
Regarding Mac and Apple Silicon: we found no support statement from Black Forest Labs as of October 16, 2026. We do not claim the model works or does not work on Macs. Check our Mac status page for details.
API pricing
Black Forest Labs offers hosted access through its API (https://api.bfl.ai/v1/flux-3-image-klein). According to BFL’s pricing page, editing an image costs the same as generating a new one. fal.ai lists the same prices and marks them as “Planned”.
| Resolution | BFL API price | fal.ai Status |
|---|---|---|
| 768 px | $0.008 per image | $0.008 (Planned) |
| 1K | $0.009 per image | $0.009 (Planned) |
| 2K | $0.014 per image | $0.014 (Planned) |
| 4K | $0.036 per image | $0.036 (Planned) |
On Replicate, only a community LoRA version (replicate/flux-3-klein-image-lora) was found, billed by run time on an L40S GPU rather than a fixed per-image price. On Together AI, no Klein listing was found (its “FLUX 3” listing is a video model). See the API documentation guide for request formats.
About Klein Studio and free limits
Klein Studio (flux3klein.org) is an unofficial website. It is not affiliated with or endorsed by Black Forest Labs. The site runs FLUX 3 Klein through Black Forest Labs’ API, supporting text-to-image generation and single-image editing on the home page.
Every visitor gets 3 free images per day at 1K resolution with no sign-up required. For more, there are one-time packs with no subscription: 150 images for $7.90, 500 images for $19.90 or 1000 images for $29.90. Images do not expire, unused images can be refunded within 14 days, and failed generations are not charged. Full details are on the pricing page.