AIRadar
Stable Diffusion logo

Stable Diffusion

The open source image model you can run on your own PC.

Price: Free locally (open models). Stability's APIs and services are pay-as-you-go.
Platforms: Windows · Linux · Mac · Web
Free plan: yes
API available: yes
Open source: yes
Available in Spanish: no
No watermark: yes

We review pricing and features regularly, but check them on the official site before subscribing. How we review.

What is Stable Diffusion?

Stable Diffusion is Stability AI's family of open source image generation models, the one that popularised generative AI. You can run it free on your own computer (with a decent GPU), fine-tune it with your own styles (LoRA), or use it from thousands of interfaces and services such as ComfyUI or the Stability APIs. Maximum freedom and control, with no censorship or subscriptions.

Pros

  • Completely free when run on your own hardware
  • Total control: fine-tunable models, LoRAs, ControlNet, no watermark
  • Huge community ecosystem (ComfyUI, Automatic1111, CivitAI)
  • No generation limits and no dependence on the cloud

Cons

  • Running it locally requires a powerful GPU and technical know-how
  • The best results require learning prompt engineering and workflows
  • The most recent base models trail Midjourney or Flux on out-of-the-box quality

What Stable Diffusion is like in practice

Where it stands out

It is the only one in its class you can download and run on your own machine with no per-image cost and nothing leaving it. Around it sits an ecosystem no closed model has: controlling exact pose, keeping a character consistent across images, applying a style you trained yourself.

Where it falls short

The entry curve is real: parameters, derivative models, extensions and a huge community that assumes a lot. In per-generation quality it trails newer models, especially with text and hands. If you just want good images from a sentence, there is effort here you do not need.

How its pricing works

The model is free and running it locally costs nothing per image; what costs is a capable graphics card, worth the same as several years of subscription. If you already own the hardware, the comparison changes entirely. There are lightweight variants for modest machines and services that host it cheaply.

Is Stable Diffusion right for you?

Yes, if…

You want total control at zero cost: models you can fine-tune on your own images, LoRAs, ControlNet, and no censorship or watermark. The community ecosystem is unrivalled.

No, if…

You want good results without learning anything: it demands a GPU, setup and prompt engineering. If you want immediate quality, Midjourney delivers from the first minute.

Frequently asked questions

Is Stable Diffusion free?

Yes, the models are open source and you can run them free on your computer. If you prefer the cloud, there are pay-as-you-go APIs and third-party sites.

What do I need to run it locally?

A GPU with at least 6-8 GB of VRAM (12+ is better) and an interface such as ComfyUI or Automatic1111. There are guides to install it in minutes.

Can I train my own styles?

Yes, that is its big advantage: you can fine-tune models or create LoRAs with your own images and styles, which is impossible on closed services.

Compare Stable Diffusion head to head

Pricing, features and limits of Stable Diffusion against its direct rivals.

Where Stable Diffusion appears

Rankings where we have picked this tool.

Alternatives to Stable Diffusion