FLUX 3 Image Klein: What It Is, Price & VRAM
FLUX 3 Image Klein is a 5.6B FLUX 3 model you can download and run yourself: text to image, edits, ten references, bounding boxes. Price, license, VRAM.
Flux 3 Image Team
FLUX 3 Image Klein is a 5.6 billion parameter FLUX 3 model whose weights you can download and run on your own GPU. One checkpoint covers text-to-image, editing, multi-reference composition, and bounding-box layouts. Black Forest Labs released it on October 15, 2026. This guide covers only what Black Forest Labs has published about it, read on October 20, 2026.
TL;DR
- What it is: the smaller, downloadable sibling of FLUX 3 Image, released by Black Forest Labs on October 15, 2026.
- Size: 5.6B parameters for the image model, shipped as a distilled checkpoint for fast generation and an undistilled Base checkpoint for fine-tuning.
- What it does: text to image, editing by instruction, up to ten reference images, and bounding boxes that place each element.
- Price on BFL's API: $0.009 per 1K image, $0.014 at 2K, $0.036 at 4K. Editing costs the same.
- License: FLUX Kommunity License. Non-commercial use is allowed, and commercial image generation is allowed for users under US$5M in annual revenue; above that you need a commercial license from BFL.
- On this site: the FLUX 3 Image Klein generator runs it in your browser, from 4 credits per image. No GPU needed.
FLUX 3 Image Klein at a glance
| FLUX 3 Image Klein | |
|---|---|
| Maker | Black Forest Labs |
| Released | October 15, 2026 |
| Parameters | 5.6B image transformer, plus a separate Qwen3-VL-4B text encoder |
| Checkpoints | Klein (distilled, 16 steps) and Klein Base (undistilled, 50 steps) |
| Modes | Text to image, editing, multi-reference composition |
| References | Up to 10 per request; the first one sets the output size |
| Layout control | Bounding boxes, [top, left, bottom, right] |
| Output | Up to native 4K on BFL's API |
| Weights | Hugging Face, black-forest-labs/flux-3-image-klein |
| License | FLUX Kommunity License (weights); Apache 2.0 (code, prompt upsampler) |
| BFL API price (1K) | $0.009 per image |
What FLUX 3 Image Klein can do
BFL calls Klein the strongest image model you can download today, and pitches it as close to its hosted models in quality while staying fast and easy to customize. That is BFL's own claim; we have not seen an independent benchmark that confirms it.
Text to image
Klein renders photography, illustration, and type in one model. BFL's samples include macro wildlife, claymation, linocut, anime, infographics, and seed-packet lettering. The cover of this article is one of them: a red fox asleep in a vintage suitcase on a train.
BFL's model card is direct about prompts: do not use the model without its prompt upsampler, because short prompts produce generic images. The upsampler is a separate 9B vision-language model, released alongside Klein under Apache 2.0, that expands your prompt before generation. It is on by default in BFL's reference code.
Editing that leaves the rest alone
Attach an image and write the change. BFL shows targeted edits that keep everything else in place, and several edits at once. One of its published examples, with the instruction BFL used:
Multi-reference composition
Klein takes a prompt and up to ten reference images and returns one image. The first reference sets the output size. Refer to each image by its position and say what it contributes, the same way you prompt the full FLUX 3 Image.
Bounding boxes
Klein shares FLUX 3 Image's layout control. You give each element a short description and a box, listed as [top, left, bottom, right]. On BFL's API, coordinates run from 0 to 1000 along each side of the frame whatever the aspect ratio; BFL's reference code uses fractions from 0 to 1 instead. The same boxes can also target an edit on an existing image.
Our bounding box guide walks through the format with prompts you can copy.
FLUX 3 Image Klein vs FLUX 3 Image
Klein and FLUX 3 Image do the same jobs. The difference is size, where they run, and how you pay.
| FLUX 3 Image Klein | FLUX 3 Image | |
|---|---|---|
| Weights | Open, downloadable | Not released; hosted only |
| Run it | Your own GPU, BFL's API, or this site | BFL's API, or a hosted app such as this one |
| Text to image | Yes | Yes |
| Editing | Yes | Yes |
| References | Up to 10 | Up to 10 |
| Bounding boxes | Yes | Yes |
| Fine-tuning, LoRA | Yes, on Klein Base | No open weights to train |
| Price here | 4 credits at 1K, 14 at 4K | 18 credits at 1K, 245 at 4K |
Pick Klein if you want to self-host, fine-tune on your own images, or want the cheapest, fastest runs; on this site it costs about a fifth of FLUX 3 Image. Pick FLUX 3 Image for BFL's larger hosted model, or for bounding-box layouts in this workbench. BFL has not published a head-to-head quality comparison between the two, so we will not invent one.
How to run FLUX 3 Image Klein
In your browser
The FLUX 3 Image Klein generator on this site needs no download or GPU: sign in, write a prompt or attach images, and pay per image in credits.
On your own GPU
The weights are on Hugging Face: black-forest-labs/flux-3-image-klein for the distilled model and black-forest-labs/flux-3-image-klein-base for the undistilled one. BFL's reference code is on GitHub at black-forest-labs/flux-3-image-klein, and the model is supported in ComfyUI and Diffusers.
Plan the memory before you download:
- BFL's model card measures peak memory at 1024×1024 on a B200 with the prompt upsampler off: about 31 GB in BF16, 26 GB in FP8, and 25 GB in NVFP4.
- The prompt upsampler adds about 28 GB on an 80 GB GPU. The distilled model plus upsampler and safety classifier is about a 52 GB download.
- BFL says Klein runs on a single consumer GPU. Its README points to INT8 files in ComfyUI for 8 GB cards such as the RTX 3070; the reference code itself has no INT8 path.
- On one H200 at 1 megapixel, BFL measured about 3 seconds per image for the distilled model and 12 seconds for Base.
Through BFL's API
BFL sells Klein per image, with text-to-image and editing priced the same:
| Output size | Price per image |
|---|---|
| 768 × 768 | $0.008 |
| 1K | $0.009 |
| 1.5K | $0.011 |
| 2K | $0.014 |
| 4K | $0.036 |
Prices are from BFL's pricing documentation, read October 20, 2026. BFL lists three extras for the hosted version: automatic prompt expansion, precise edits, and 4K output.
The license, in plain terms
The weights ship under the FLUX Kommunity License v1.0. It allows non-commercial use, plus commercial image generation by users with less than US$5 million in gross annualized revenue, affiliates included. Larger companies, and anyone who wants to run Klein inside a product at scale, need a commercial license from BFL. The card also says the commercial exception is not blanket permission for commercial fine-tuning or redistribution. Read the license on the model card before you ship anything; this summary is not legal advice.
Can I use FLUX 3 Image Klein on this site?
Yes. The FLUX 3 Image Klein generator runs it in your browser: text to image, editing by instruction, and up to ten references, at 1K, 2K, or 4K. It costs 4, 6, or 14 credits per image, shown on the prompt box before you run. The same page can switch to the full FLUX 3 Image model.
We are an independent workbench, not affiliated with, endorsed by, or sponsored by Black Forest Labs. FLUX is their trademark, used here only to identify the models we write about and provide access to.
Timeline
- July 23, 2026: Black Forest Labs announces the FLUX 3 family.
- October 2, 2026: BFL's FLUX 3 Image model page and documentation are publicly available.
- October 15, 2026: BFL releases FLUX 3 Image Klein with open weights.
FAQs about FLUX 3 Image Klein
What is FLUX 3 Image Klein?
A 5.6B-parameter FLUX 3 image model that you can download and run on your own hardware. It handles text to image, editing, up to ten references, and bounding-box layouts in one model. Black Forest Labs released it on October 15, 2026.
Is FLUX 3 Image Klein open source and free?
The weights are open and free to download, but the license is not open source. The FLUX Kommunity License allows non-commercial use and commercial generation for users under US$5M in annual revenue; larger companies need a commercial license from BFL.
Can FLUX 3 Image Klein edit images?
Yes. It edits an image from a written instruction, can make several edits at once, and leaves the rest of the image in place. Bounding boxes can target where an edit lands.
How many reference images does FLUX 3 Image Klein accept?
Up to ten per request. The first reference sets the output size.
How much VRAM does FLUX 3 Image Klein need?
BFL measured 25 to 31 GB peak at 1024×1024 on a B200, depending on precision, with the prompt upsampler off. BFL says it runs on a single consumer GPU, and points to INT8 files in ComfyUI for 8 GB cards.
How much does the FLUX 3 Image Klein API cost?
On BFL's API, $0.008 at 768×768, $0.009 at 1K, $0.011 at 1.5K, $0.014 at 2K, and $0.036 at 4K per image. Editing costs the same as text to image.
Is FLUX 3 Image Klein the same as FLUX.2 klein?
No. FLUX.2 klein was the small model of the previous FLUX.2 generation. FLUX 3 Image Klein is the FLUX 3 generation's open-weights image model, released October 15, 2026.
Can I use FLUX 3 Image Klein on Flux 3 Image?
Yes, on the FLUX 3 Image Klein generator, from 4 credits per image. See the pricing page for plans.
Sources: Black Forest Labs, bfl.ai/models/flux-3-image-klein; BFL pricing documentation (docs.bfl.ai); Hugging Face model card black-forest-labs/flux-3-image-klein; GitHub black-forest-labs/flux-3-image-klein README; bfl.ai/blog. Read October 20, 2026. Images on this page are official FLUX 3 Image Klein samples by Black Forest Labs, not generated by this site.