Model reference · open weights

FLUX.1-schnell

Image black-forest-labs Text→image 3 builds Open weights 630k dl/mo

FLUX.1-schnell is an open-weight image model from Black Forest Labs. FLUX.1-schnell (BF16) weighs 33.7 GB; the smallest configuration that runs it is RTX 5090 32 GB.

For self-hosting, compare this build's requirements below with the GPU you plan to rent.

  • FLUX.1-schnell is a text-to-image model developed by Black Forest Labs that uses a 11.9 billion parameter rectified flow transformer architecture.
  • It generates high-quality images from English text prompts in 1 to 4 steps and is released under the apache-2.0 licence for personal, scientific, and commercial use.

Summary of the black-forest-labs/FLUX.1-schnell model card, 2026-10-01. The estimate below is for another build of the family.

What it is

Released byBlack Forest Labs
Released2024-07-31
Parameters11.9B
VRAM33.7 GB for the weights

What it runs on

Memory and cards for FLUX.1-schnell (BF16)

33.7 GBweights, file size
23.8 GBbiggest part
5.0 GBworking memory, one 1024² image
537 MBruntime overhead
CardOne imageMemory
RTX 3060 12 GB … RTX 4090 24 GBdoes not fit
RTX 5090 32 GBtight (encoders offloaded)31.0 GB
L40S 48 GBtight44.0 GB
A100 80 GBfits78.2 GB
H100 80 GBfits78.1 GB
RTX PRO 6000 Blackwell 96 GBfits93.8 GB
DGX Spark (GB10) 128 GB unifiedfits107 GB
H200 141 GBfits138 GB
B200 180 GBfits176 GB

Builds

Sizes, precisions & builds

BuildParamsPrecisionWeightsSmallest setup
FLUX.1-schnell ↗ 11.9BBF16 33.7 GBRTX 5090 32 GB
FLUX.1-schnell-GGUF ↗
packaged by unsloth
15 builds: Q2_K 4.0 GB … F16 23.8 GB
the transformer alone, to use with the text encoders and VAE
GGUF 6.9 GBRTX 4060 Ti 16 GB
FLUX.1-schnell (above) ↗
packaged by unsloth
11.9BBF16 33.7 GBRTX 5090 32 GB

From the model card

What Black Forest Labs says about FLUX.1-schnell

Read the model card

FLUX.1 [schnell] is a 12 billion parameter rectified flow transformer capable of generating images from text descriptions. For more information, please read our blog post.

Key Features

  1. Cutting-edge output quality and competitive prompt following, matching the performance of closed source alternatives.
  2. Trained using latent adversarial diffusion distillation, FLUX.1 [schnell] can generate high-quality images in only 1 to 4 steps.
  3. Released under the apache-2.0 licence, the model can be used for personal, scientific, and commercial purposes.

Usage

We provide a reference implementation of FLUX.1 [schnell], as well as sampling code, in a dedicated github repository. Developers and creatives looking to build on top of FLUX.1 [schnell] are encouraged to use this as a starting point.

API Endpoints

The FLUX.1 models are also available via API from the following sources

ComfyUI

FLUX.1 [schnell] is also available in Comfy UI for local inference with a node-based workflow.

Diffusers

To use FLUX.1 [schnell] with the 🧨 diffusers python library, first install or upgrade diffusers

pip install -U diffusers

Then you can use FluxPipeline to run the model

import torch
from diffusers import FluxPipeline
pipe = FluxPipeline.from_pretrained("black-forest-labs/FLUX.1-schnell", torch_dtype=torch.bfloat16)
pipe.enable_model_cpu_offload() #save some VRAM by offloading the model to CPU. Remove this if you have enough GPU power

prompt = "A cat holding a sign that says hello world"
image = pipe(
    prompt,
    guidance_scale=0.0,
    num_inference_steps=4,
    max_sequence_length=256,
    generator=torch.Generator("cpu").manual_seed(0)
).images[0]
image.save("flux-schnell.png")

To learn more check out the diffusers documentation


Limitations

  • This model is not intended or able to provide factual information.
  • As a statistical model this checkpoint might amplify existing societal biases.
  • The model may fail to generate output that matches the prompts.
  • Prompt following is heavily influenced by the prompting-style.

Out-of-Scope Use

The model and its derivatives may not be used

  • In any way that violates any applicable national, federal, state, local or international law or regulation.
  • For the purpose of exploiting, harming or attempting to exploit or harm minors in any way; including but not limited to the solicitation, creation, acquisition, or dissemination of child exploitative content.
  • To generate or disseminate verifiably false information and/or content with the purpose of harming others.
  • To generate or disseminate personal identifiable information that can be used to harm an individual.
  • To harass, abuse, threaten, stalk, or bully individuals or groups of individuals.
  • To create non-consensual nudity or illegal pornographic content.
  • For fully automated decision making that adversely impacts an individual's legal rights or otherwise creates or modifies a binding, enforceable obligation.
  • Generating or facilitating large-scale disinformation campaigns.

Quoted from the model card on Hugging Face. The full card is behind the Hugging Face link above.

Running it yourself

Run it on a rented GPU

Rent a machine by the hour. ComfyUI is installed on it. Open ComfyUI through the tunnel, then Templates → Flux.1 Schnell Full: Text to Image: it loads ComfyUI's own build of this model, the files above.

# on your rented machine (the ssh line is on its page in the console)
# get REPO FILE FOLDER: one file into /workspace/models/FOLDER, where ComfyUI loads it from
get() { hf download "$1" "$2" --local-dir /workspace/hf-files && mkdir -p "/workspace/models/$3" && mv "/workspace/hf-files/$2" "/workspace/models/$3/$4"; }

# the files of the template “Flux.1 Schnell Full: Text to Image” (31.8 GB)
get Comfy-Org/Lumina_Image_2.0_Repackaged split_files/vae/ae.safetensors vae
get comfyanonymous/flux_text_encoders clip_l.safetensors text_encoders
get comfyanonymous/flux_text_encoders t5xxl_fp16.safetensors text_encoders
get Comfy-Org/flux1-schnell flux1-schnell.safetensors diffusion_models

start-comfyui
Renting a GPU: connect, tunnels, ComfyUI
# on your computer, in a second terminal: ComfyUI in your browser at http://localhost:8188
# HOST, PORT and BOOKING are your machine's, from its page in the console
ssh -o HostKeyAlias=axforge-BOOKING -o StrictHostKeyChecking=accept-new -L 8188:localhost:8188 dev@HOST -p PORT
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