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Black Forest Labs (FLUX.2 [klein] family, released 15 January 2026)

FLUX.2 [klein] 9B Base

The undistilled 9-billion-parameter FLUX.2 [klein] model from Black Forest Labs, running in your browser: text to image and edits with up to 3 reference images, no GPU and no download.

Architecture
9-billion-parameter rectified flow transformer; ComfyUI pairs it with a Qwen 3 8B text encoder and the FLUX.2 VAE
Training
No step or guidance distillation — the undistilled base of the 9B [klein] model
Abilities
Text to image, image to image and multi-reference editing
Weights
Open, BF16, under the FLUX Non-Commercial License (the 4B [klein] models are Apache 2.0); ComfyUI also lists an FP8 file
Local hardware
About 29 GB of VRAM per the model card; the Diffusers example uses 50 steps and guidance 4.0 at 1024×1024
On Kenerate
kenerate/flux-2-klein-base-9b — text to image and edit with up to 3 references, 8 sizes up to 1536×1536, seed control
Try
  • FLUX.2 [klein] 9B Base
  • Fisherman on a misty harbour — FLUX.2 klein 9B Base output
  • Rainy ramen stall in Osaka — FLUX.2 klein 9B Base output
  • LISBOA travel poster — FLUX.2 klein 9B Base output
  • Glacier lake in Patagonia — FLUX.2 klein 9B Base output
  • Real outputs
  • Official sources
  • Free to start
  • No watermark

Updated by the

Made with Kenerate

What is FLUX.2 [klein] 9B Base?

Updated

What is FLUX.2 [klein] 9B Base?

FLUX.2 [klein] 9B Base is Black Forest Labs' 9-billion-parameter rectified flow transformer for text to image and multi-reference editing, trained without step or guidance distillation so it keeps full flexibility for fine-tuning and LoRA work. Weights are under the FLUX Non-Commercial License and need about 29 GB of VRAM locally. On Kenerate AI it runs in the browser for 4.5 credits per image, with up to 3 reference images for edits.

Key facts

Official name
FLUX.2 [klein] 9B Base
Hugging Face ID
black-forest-labs/FLUX.2-klein-base-9B
Maker
Black Forest Labs
Size
9B parameters · BF16
Distillation
None (base model)
Licence
FLUX Non-Commercial
Local VRAM
≈29 GB (RTX 4090 and up)
References
Up to 3
Max size on Kenerate
1536×1536

Models

FLUX.2 [klein] 9B Base on Kenerate

Every version in the generator, and what each is good at.

  • Flux 2 Klein Base 9B title card — a richly detailed macro photograph of a dew-covered fern frond with a tiny iridescent beetle

    Black Forest Labs

    Flux 2 Klein Base 9B

    Reference images
    Up to 3
    Output
    1536 px

    Best for

    This model — undistilled 9B

    Open Flux 2 Klein Base 9B
  • Flux 2 Klein Base 4B title card — a raw

    Black Forest Labs

    Flux 2 Klein Base 4B

    Reference images
    Up to 3
    Output
    1536 px

    Best for

    Smaller undistilled base

    Open Flux 2 Klein Base 4B
  • Flux 2 Klein title card — a row of quick concept sketches of a futuristic car evolving left to right into one polished glossy render
    Free plan

    Black Forest Labs

    Flux 2 Klein

    Reference images
    Up to 3
    Output
    1536 px

    Best for

    Fast 4B, free plan

    Open Flux 2 Klein
  • Flux 2 Dev title card — a photoreal rainy neon city street at dusk
    Free plan

    Black Forest Labs

    Flux 2 Dev

    Reference images
    Up to 3
    Output
    2048 px

    Best for

    32B all-rounder, free plan

    Open Flux 2 Dev
  • Flux 2 Pro title card — a polished professional advertising photograph of a luxury mechanical wristwatch on black slate with water droplets and a single hard key light

    Black Forest Labs

    Flux 2 Pro

    Reference images
    Up to 3
    Output
    2048 px

    Best for

    Hosted, higher fidelity

    Open Flux 2 Pro

From our tests

Strengths and limits

Good at

  • Natural photo detail at 1024 px — skin texture and knitwear on the fisherman portrait, wet-pavement reflections on the ramen stall.
  • Clean large Latin lettering: “LISBOA” on the travel poster came out spelled right on the first try.
  • Range from one prompt style: product shots, landscapes, flat posters and watercolor all worked without extra settings.
  • Cheap for a 9B model — 4.5 credits per image in the browser, versus about 29 GB of VRAM to run it yourself.

Limits

  • Small and non-Latin text breaks down: the Japanese signs on the ramen stall and the fox's book cover are gibberish.
  • Not on Kenerate's free plan — use Flux 2 Klein (4B) or Flux 2 Dev for free drafts.
  • Up to 3 reference images, fewer than Seedream 5.0 (10) or GPT Image 2 (16).
  • The open weights are non-commercial; check Black Forest Labs' licence before using a self-hosted copy commercially.

How to

How to use FLUX.2 [klein] 9B Base on Kenerate

  1. Step 1

    Open the model

    Go to /app/image and pick Flux 2 Klein Base 9B (the button on this page selects it for you). Sign in free to get started.

  2. Step 2

    Write the prompt

    Describe medium, subject, setting, light and camera in plain sentences. Put exact on-image words in quotes.

  3. Step 3

    Pick a size and seed

    Choose one of 8 sizes up to 1536×1536 and fix the seed when you want to compare prompt changes.

  4. Step 4

    Edit with references

    Upload up to 3 images and say what changes and what stays — an edit costs 6.3 credits.

Kenerate AI Image Studio with a text prompt typed into the prompt box

Open Image Studio and type what you want to see — subject, style, lighting and mood.

1 / 5 · Describe your image

Watch the tour · 1:23

Prompts, styles, references, edit, Arena & chat

Chapters

FAQ

FLUX.2 [klein] 9B Base questions

What is FLUX.2 [klein] 9B Base?

FLUX.2 [klein] 9B Base is a 9-billion-parameter rectified flow transformer from Black Forest Labs, published on Hugging Face as black-forest-labs/FLUX.2-klein-base-9B. It generates images from text and edits them with multiple references. “Base” means it was trained without step or guidance distillation, which keeps it flexible for fine-tuning, LoRA training and research.

Link to this answer

What is the difference between FLUX.2 klein 9B Base and FLUX.2 klein 9B?

The base model is undistilled: it keeps the full sampling process and classifier-free guidance, so it needs more steps (the model card's example uses 50) but is the better starting point for fine-tunes and LoRAs. The distilled FLUX.2 [klein] 9B is tuned for speed and needs far fewer steps. Black Forest Labs says the base suits work “where control matters more than speed”.

Link to this answer

Can I use FLUX.2 klein 9B Base online without a GPU?

Yes. Kenerate AI runs it in the browser as Flux 2 Klein Base 9B, with no download or setup. It costs 4.5 credits per image and 6.3 per edit, takes up to 3 reference images and offers 8 sizes up to 1536×1536. Running the weights yourself needs about 29 GB of VRAM, per the model card.

Link to this answer

Is FLUX.2 klein 9B Base free?

The weights are free to download from Hugging Face after you accept the licence, but you need your own high-VRAM GPU. On Kenerate the 9B Base is a paid model (4.5 credits per image from a one-time credit pack, no subscription). The free plan includes Flux 2 Klein (4B) and Flux 2 Dev if you want free FLUX.2 images.

Link to this answer

What licence does FLUX.2 klein 9B Base use?

The 9B weights are released under the FLUX Non-Commercial License, according to the Hugging Face model card. The 4B [klein] models are Apache 2.0. Read Black Forest Labs' licence before using a self-hosted 9B model commercially; images you generate on Kenerate follow Kenerate's terms of service.

Link to this answer

What is black-forest-labs/FLUX.2-klein-base-9B-fp8?

It refers to an 8-bit (FP8) copy of the same 9B Base weights, which ComfyUI lists for its FLUX.2 [klein] workflows. ComfyUI Wiki puts the full checkpoint at about 18.9 GB and the FP8 file at about 9.5 GB, so FP8 fits smaller GPUs at some cost in precision. On Kenerate you don't choose a file — the hosted model runs for you.

Link to this answer

Can FLUX.2 klein 9B Base edit images?

Yes. The model card lists multi-reference editing. On Kenerate, upload up to 3 reference images to Flux 2 Klein Base 9B and describe the change and what must stay, for example “same pose, swap the background for a beach”. Each edit costs 6.3 credits.

Link to this answer

How good is FLUX.2 klein 9B Base at text in images?

Mixed in our test. Large Latin lettering worked — “LISBOA” on a travel poster was spelled right first try — but small text and Japanese signage came out as gibberish. For posters with lots of text, try GPT Image 2 or Qwen Image on Kenerate instead.

Link to this answer

What settings does the model card recommend?

The Diffusers example on the Hugging Face card generates at 1024×1024 with 50 inference steps and a guidance scale of 4.0, and suggests CPU offload to save VRAM. Wiro's API example uses 30 steps and scale 4. On Kenerate the steps and guidance are set for you; you choose the prompt, size and seed.

Link to this answer

In depth

FLUX.2 [klein] 9B Base, in depth

Background, how to prompt it, and when to pick something else.

Base vs distilled: which FLUX.2 [klein] 9B to use

Black Forest Labs ships the 9B [klein] model twice: a distilled version tuned for speed, and this undistilled Base, trained without step or guidance distillation [1]. ComfyUI provides separate workflows for each [2].

  • Base 9B — full guidance, more steps; the starting point for fine-tunes, LoRAs and research.
  • Distilled 9B — far fewer steps, for fast generation and editing.
  • 4B [klein] — smaller and Apache 2.0; Flux 2 Klein (4B) is on Kenerate's free plan.

By Last updated and reviewed

We run these models in the Kenerate generator. Model facts come from the makers' own pages; specs and limits were checked against our code; the examples are our own outputs.

Sources: black-forest-labs/FLUX.2-klein-base-9B — Hugging Face model card · FLUX.2 [klein] tutorial — ComfyUI docs · FLUX.2 Klein 9B — ComfyUI Wiki · Flux (text-to-image model) — Wikipedia

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