FLUX 3 Image Klein
FLUX 3 Image Klein is the small model in Black Forest Labs' FLUX 3 image line, released on 15 October 2026, two weeks after FLUX 3 Image. It is a 5.6 billion parameter model with downloadable weights that generates from text, edits, and composes from up to 10 reference images, with native output up to 4K. BFL ships a base checkpoint for fine-tuning and a step-distilled one for speed; fal's endpoint is the distilled one. The weights are under the FLUX Kommunity License, which allows free commercial use for individuals and companies under $5 million in annual revenue. BFL says the INT8 build runs on an 8 GB consumer GPU.
Anvisha Pai, Co-founder & CEO, Voyager
Black Forest Labs · released
›What we asked for
A self-portrait of FLUX 3 Image Klein, a small and fast open-weights image model: a compact brass pocket camera on a workbench beside a sprawling full-size studio camera, the small one in sharp focus, a hand-lettered paper tag tied to it reading 'KLEIN', soft daylight, shallow depth of field, product photograph.
blackforestlabs/flux-3/klein/text-to-image
enable_prompt_expansion: true, image_size: {"width":1184,"height":880}, output_format: png, num_images: 1
returned 1184 by 880 pixels
At a glance
- Price
- $0.009 a 1K image on fal, the same for edits, rising to $0.036 at 4K. fal calls these planned prices and says final pricing is not yet confirmed.
- Sizes
- Any width and height from 256 to 4096 pixels, or a preset. We asked for the same 1 megapixel shapes FLUX 3 Image returns: 1024 square, 880 by 1184, 1184 by 880 and 1568 by 672.
- Speed
- 1.4 to 8.3 seconds a request in our run, median about 3, including the trip to fal. The edit took 4.3 seconds.
- Open weights
- Base and step-distilled checkpoints on Hugging Face under the FLUX Kommunity License: free commercial use under $5 million in annual revenue, a paid licence above it.
- References and boxes
- Edits take up to 10 reference images, and both endpoints accept optional bounding boxes to place, move or remove named objects.
Other FLUX models: FLUX 3 Image, FLUX.2 Pro, FLUX.2 Flex, FLUX.2 Max, FLUX 3 Max. Compare all 6.
Anvisha's take
This is the surprise of the October batch. At under a cent an image and three seconds a picture, Klein set the poster and the four-step infographic word for word, placed all five objects in the composition test exactly, and made one of the cleanest edits on the roster: the dripper turned forest green, a brass handle appeared on the right, and nothing else moved. FLUX 3 Image, at five times the price and eight times the wait, left that dripper black. Its misses are the ones you would expect of a small model: the logo mark is a thin chain link with a spike through it, and the chart's bars are in the right order on an axis that reads 300, 550, 100, 150, 200, 250, 0. Prompt expansion is on by default and I left it on; it did not add copy anywhere. For drafts, edits and anything you will run thousands of times, this is the FLUX I would reach for first.
FLUX 3 Image Klein real output: the same 12 prompts every model gets
Every image model on this site gets the same 12 prompts, so you can compare like with like. These are the pictures FLUX 3 Image Klein returned, one try each, nothing re-rolled or retouched. Generated on . The 12 pictures took 1 to 8 seconds each and cost $0.108 in total.
Spelling, kerning and hierarchy of three lines of set text.
›What we asked for
A concert poster that reads 'MODA SUMMER SESSIONS' in large bold type, with the subtitle 'Friday 12 June, 8pm, Roundhouse' and a smaller line 'Tickets at the door'. Risograph style, two colours, tangerine and navy, grainy ink texture.
blackforestlabs/flux-3/klein/text-to-image
enable_prompt_expansion: true, image_size: {"width":880,"height":1184}, output_format: png, num_images: 1
returned 880 by 1184 pixels
Catalogue lighting, a clean seamless background and a believable contact shadow.
›What we asked for
Studio product photograph of a matte black ceramic pour-over coffee dripper on a seamless white background, soft top light, subtle contact shadow, centred, catalogue style.
blackforestlabs/flux-3/klein/text-to-image
enable_prompt_expansion: true, image_size: {"width":1024,"height":1024}, output_format: png, num_images: 1
returned 1024 by 1024 pixels
A natural face, correct finger count and hands holding an object.
›What we asked for
Close-up portrait of a woman in her 40s with short grey hair, laughing, holding a red ceramic mug with both hands, natural window light, 85mm lens, shallow depth of field.
blackforestlabs/flux-3/klein/text-to-image
enable_prompt_expansion: true, image_size: {"width":880,"height":1184}, output_format: png, num_images: 1
returned 880 by 1184 pixels
A flat single-colour mark with a legible wordmark and no gradients or photo texture.
›What we asked for
A flat vector logo mark for a bicycle repair shop called 'Spoke & Chain': a single-colour icon combining a chain link and a wheel spoke, with the wordmark below in a geometric sans-serif, black on white.
blackforestlabs/flux-3/klein/text-to-image
enable_prompt_expansion: true, image_size: {"width":1024,"height":1024}, output_format: png, num_images: 1
returned 1024 by 1024 pixels
Many distinct objects and people in one frame without merging or duplicating them.
›What we asked for
A crowded Saturday farmers market seen from slightly above: at least twelve stalls with striped awnings, shoppers carrying tote bags, a dog on a leash, crates of oranges, a musician with a guitar, bunting overhead, late morning light.
blackforestlabs/flux-3/klein/text-to-image
enable_prompt_expansion: true, image_size: {"width":1184,"height":880}, output_format: png, num_images: 1
returned 1184 by 880 pixels
A named historical style applied faithfully rather than a generic painterly look.
›What we asked for
A lighthouse on a rocky cliff during a storm, in the style of a Japanese ukiyo-e woodblock print, with visible wood grain texture, flat colour areas and a bokashi gradient sky.
blackforestlabs/flux-3/klein/text-to-image
enable_prompt_expansion: true, image_size: {"width":880,"height":1184}, output_format: png, num_images: 1
returned 880 by 1184 pixels
Six labelled bars at the stated heights, in order, with readable axes.
›What we asked for
A clean bar chart titled 'Monthly active users' showing six months, January through June, with the values 120, 150, 180, 170, 220 and 260, labelled axes, white background, one accent colour, no 3D effects.
blackforestlabs/flux-3/klein/text-to-image
enable_prompt_expansion: true, image_size: {"width":1184,"height":880}, output_format: png, num_images: 1
returned 1184 by 880 pixels
A 21:9 composition that leaves the left third clear for headline text.
›What we asked for
Website hero banner: a wide panorama of a sunlit modern co-working space with plants, the left third of the frame kept as clear wall space for text, warm neutral palette.
blackforestlabs/flux-3/klein/text-to-image
enable_prompt_expansion: true, image_size: {"width":1568,"height":672}, output_format: png, num_images: 1
returned 1568 by 672 pixels
Four numbered steps in the given order with their exact wording, plus an icon each.
›What we asked for
An infographic card titled 'How to brew pour-over' with four numbered steps in this order: 1. Rinse the filter, 2. Bloom for 30 seconds, 3. Pour in slow circles, 4. Wait 3 minutes. A simple icon beside each step, muted palette, clean sans-serif type.
blackforestlabs/flux-3/klein/text-to-image
enable_prompt_expansion: true, image_size: {"width":880,"height":1184}, output_format: png, num_images: 1
returned 880 by 1184 pixels
Appetising, menu-grade food with correct textures and no melted anatomy.
›What we asked for
Overhead photograph of a margherita pizza on a wooden board, fresh basil leaves, one slice pulled out with the cheese stretching, restaurant menu photography, natural light.
blackforestlabs/flux-3/klein/text-to-image
enable_prompt_expansion: true, image_size: {"width":1024,"height":1024}, output_format: png, num_images: 1
returned 1024 by 1024 pixels
Exact counts and left-right placement of five named objects.
›What we asked for
A glass of water on a wooden table with exactly three ice cubes in it, a yellow pencil resting across the rim of the glass, a blue book to the left of the glass and a red apple to the right, photographed from table height.
blackforestlabs/flux-3/klein/text-to-image
enable_prompt_expansion: true, image_size: {"width":1184,"height":880}, output_format: png, num_images: 1
returned 1184 by 880 pixels
Change one object's colour and add a part while leaving background, light and framing untouched.
›What we asked for
Change the coffee dripper to a deep forest green and add a small brass handle on its right side. Keep the background, lighting and composition exactly as they are. (applied to the product on white result above)
blackforestlabs/flux-3/klein/edit-image
enable_prompt_expansion: true, image_size: {"width":1024,"height":1024}, output_format: png, num_images: 1
returned 1024 by 1024 pixels
How the cost under each picture was worked out: fal's planned $0.009 per 1K image for FLUX 3 Image Klein, generation and editing alike, final pricing not yet confirmed (fal.ai/models/blackforestlabs/flux-3/klein/text-to-image, read 2026-10-22); fal does not return the charge.
Compare FLUX 3 Image Klein
FLUX 3 Image Klein pricing
| Where | Unit | Price | Source |
|---|---|---|---|
| fal | 1K image Generation and editing alike. fal labels these planned prices and says final pricing is not yet confirmed; its pricing API reports $0.009 per megapixel, which agrees for a 1 MP image. | $0.009 | fal model page, read |
| fal | 768 by 768 image | $0.008 | fal model page, read |
| fal | 2K image $0.011 at 1.5K. | $0.014 | fal model page, read |
| fal | 4K image | $0.036 | fal model page, read |
| BFL API | 1K image BFL says pricing starts at this figure for the distilled model; it lists no other tiers in the announcement. | $0.009 | BFL announcement, read |
Is FLUX 3 Image Klein free?
The weights are free to download and, under the FLUX Kommunity License, free to use commercially for individuals and companies with under $5 million in annual revenue. Hosted use on BFL's API, fal and others is paid per image.
- •Weights: base and distilled checkpoints on Hugging Face, with FP8, INT8 and NVFP4 builds.
- •Licence: free commercial use below $5 million annual revenue; larger companies need BFL's self-hosting licence or the API.
- •Hosted: per image, from $0.009 at 1K on fal and BFL's API.
BFL announcement, read
Where to use FLUX 3 Image Klein
- Hugging Face · Base and step-distilled weights under the FLUX Kommunity License.
- BFL API · Black Forest Labs' own API and Playground.
- fal · blackforestlabs/flux-3/klein/text-to-image and /klein/edit-image, the step-distilled model; the endpoints used for the samples below.
- Voyager · Runs inside Voyager, the agent for creative work, with your own fal key.
Voyager
Run FLUX 3 Image Klein inside Voyager
Voyager is an agent for creative work that runs every model in this reference, FLUX 3 Image Klein included. Brief it, and it picks the model, makes the thing and hands back something you can edit. Create an account to get started.
What we noticed running FLUX 3 Image Klein
- •Both changes made, the body forest green and a brass handle on the right, with the shape, the hole in the cone, the base and the background unchanged. FLUX 3 Image left the body black on the same request. See the edit an existing image picture.
- •Book left, apple right, three ice cubes and the pencil resting across the rim, as asked. See the hard composition picture.
- •All three lines correct and nothing added: a two-colour risograph poster with a crowd of raised hands. See the text in an image picture.
- •Four steps in order with exactly the given wording, an icon each, and no invented sub-copy. See the infographic with steps picture.
- •Title and months right, bars in the right order, but no value labels and a y-axis reading 300, 550, 100, 150, 200, 250, 0 from top to bottom. See the chart picture.
- •Wordmark spelled right with no tagline, but the mark is a thin chain link with a spike through it, more a pin than a wheel. Faint blotches show in the white background. See the logo mark picture.
- •A plain footed cone with no ribs and no handle, on a slightly grey, faintly mottled background. See the product on white picture.
- •Busker with a guitar, one golden retriever on a lead, oranges in crates and bunting, but only about five awnings in view where we asked for twelve stalls. See the busy scene picture.
- •The left third is a bare wall with nothing painted on it, at a true 1568 by 672. See the wide aspect ratio picture.
- •Every request returned in 1.4 to 8.3 seconds, median about 3; FLUX 3 Image took 21 to 40 seconds for most of the same prompts.
FLUX 3 Image Klein limits and API parameters
| Limit | Value |
|---|---|
| Output size | 256 to 4096 pixels per side, native 4K. fal API schema, read |
| Reference images | Up to 10 per edit request. fal API schema, read |
| Images per request | Up to 4. fal API schema, read |
| Local hardware | 11.2 GB of weights in BF16, 5.6 GB in FP8; BFL says the INT8 build runs on GeForce RTX cards with 8 GB of VRAM. BFL announcement, read |
›Every setting, for developers
fal (blackforestlabs/flux-3/klein/text-to-image and /edit-image)
fal API schema, read
| Parameter | Type | Values | Default |
|---|---|---|---|
| prompt | string | Any text Required. The model is trained on detailed captions; on edits, describe the whole target image with the change folded in. | |
| image_size | enum or object | square_hd, square, portrait_4_3, portrait_16_9, landscape_4_3, landscape_16_9, or {width, height} from 256 to 4096 per side On edits, left unset it follows a single reference's size, scaled to at most 4 megapixels. | square_hd |
| enable_prompt_expansion | boolean | true, false Expands the prompt into a detailed caption, grounded in the references when editing. | true |
| image_urls | list of URLs | 1 to 10 images Edit endpoint only, where it is required. | |
| bounding_boxes | list | Labelled boxes as fractions of the image, (0, 0) at top left Name each box in the prompt by its label. | |
| num_images | integer | 1 to 4 | 1 |
| output_format | enum | jpeg, png, webp | png |
| seed | integer | Any integer |
What FLUX 3 Image Klein will not draw
fal marks the endpoints for commercial use and runs a safety checker that is on by default; turning it off needs account authorisation. Self-hosted use is governed by the FLUX Kommunity License, which allows free commercial use only below $5 million in annual revenue.
BFL announcement, read
Alternatives to FLUX 3 Image Klein
Frequently asked questions
What is FLUX 3 Image Klein?
The small, open-weights model in Black Forest Labs' FLUX 3 image line, released on 15 October 2026: 5.6 billion parameters, text-to-image, editing and up to 10 references, native up to 4K.
How much does FLUX 3 Image Klein cost?
On fal, $0.009 for a 1K image and $0.036 at 4K, the same for edits, read on 22 October 2026; fal calls these planned prices. The weights are free for companies under $5 million in annual revenue.
Can I run FLUX 3 Image Klein locally?
Yes. The weights are on Hugging Face, and BFL says the INT8 build runs on a GeForce RTX card with 8 GB of VRAM. Commercial use above $5 million in annual revenue needs a licence.
Klein or FLUX 3 Image?
On our prompts Klein matched FLUX 3 Image on text and layout, made a better edit, and was about eight times faster at a fifth of the price. FLUX 3 Image drew a more correct chart. Start with Klein and step up when a picture needs it.
How this page is made
Prices, limits and settings are read from the linked vendor and host pages on the dates shown. Every picture was generated by us through fal with the request shown under it, and the original files are kept unedited. A generation that failed is shown as a failure. Model and vendor names are used to identify the products; no vendor imagery appears on this page.
