PROMPT GUIDE

NovelAI vs Stable Diffusion (Comparison Table and How to Choose)

NovelAI and Stable Diffusion both come up often for making anime-style illustrations. Their prompt styles are similar, but where they run, cost, effort and freedom differ a lot. This guide puts the differences in a table and suggests which to choose for different goals.

Last updated: 2026-10-22 approx. 3 min read

日本語版

The short answer

NovelAI is a paid online service that makes high-quality anime pictures easily. Stable Diffusion usually runs on your own PC (GPU) and lets you build freely with models, LoRAs and ControlNet, at the cost of setup and effort. Both use the Danbooru tag way of thinking.

What is the difference between NovelAI and Stable Diffusion? (Comparison table)

The biggest difference is whether it is an online service or runs on your own PC.

Point	NovelAI	Stable Diffusion
Where it runs	In the browser (online service)	Usually your own PC (online services exist too)
What you need	An account and a plan	A capable GPU and software setup
How costs work	Monthly plans and so on (check the official site)	Software is often free, but PC and electricity cost money
Art style	Its own models, strong at anime	Set by the model you choose (anime or photo)
Prompts	Mainly Danbooru tags plus its own emphasis syntax	Danbooru tags or sentences (depends on the model)
Freedom	Within the features provided	Fine control with LoRA, ControlNet and more
Effort	Low (start right away)	High (setup, updates, troubleshooting)

Anime girl in a school uniform under cherry blossoms, a reference for comparing services — アニメ絵の上半身

Full-body anime girl leaning forward with her hands behind her back — アニメ絵の上半身

Illustration usage rules

Rinka's tips

Prices, features and available models change for both. Check the current official information before deciding
Both use the Danbooru tag way of thinking, so the tag guides on this site help with either

Who is NovelAI best for?

People who want high-quality anime pictures right away without setting up a PC.

You do not have a PC with a GPU, or do not want to spend time on setup
You mainly make anime pictures and prefer a consistent look from the start
You want to use it the same way from a phone or different computers
You would rather leave updates and error handling to the service

For how to write NovelAI prompts (emphasis and quality tags), see How to Write NovelAI Prompts (Emphasis, Quality Tags, UC) →

Who is Stable Diffusion best for?

People who want to fine-tune on their own PC with models and add-ons.

You have a PC with a GPU and do not mind setup and research
You want to change the look freely with models and LoRAs
You want to fix the shape with poses or line art (ControlNet and so on)
You want to make a lot of images without worrying about usage limits

To start Stable Diffusion with a button-style interface, see How to Use Stable Diffusion Forge (Reading the UI and Making Your First Image) →

For the node-based ComfyUI, see How to Use ComfyUI for Beginners (Nodes and Your First Workflow) →

How do the prompts differ?

Both are tag-centered, but emphasis syntax and the handling of quality tags differ.

Item	NovelAI	Stable Diffusion
Basic style	Danbooru tags separated by commas	Danbooru tags (anime models) or sentences
Emphasis	{ }, [ ] and numeric syntax (varies by version)	Parentheses and numbers like (tag:1.2)
Quality tags	May have a setting that adds them automatically	Write the quality tags from the model page yourself
Negative	Undesired content field (UC) and presets	Negative prompt field

1girl, solo, smile, long hair, school uniform, cherry blossoms, outdoors, upper body

1girl, solo, (smile:1.2), long hair, school uniform, cherry blossoms, outdoors, upper body, masterpiece, best quality

For the detailed differences in emphasis syntax, see The Complete Guide to Prompt Weight Syntax and BREAK →

Which should you choose for your goal?

As a rule of thumb, NovelAI for an easy start, Stable Diffusion for building freely.

Steps to decide which to use

Check whether you have a PC with a GPU (if not, start with a service such as NovelAI)
Decide whether you mainly want anime, or also photos and other styles
Think about how many images you want a month and how much you can spend
Think about whether you can put time into setup and updates
Make about 10 images with one first, and try the other if something is missing

What are common doubts and mistakes?

Choosing by fit for your goal, rather than which is better, avoids most mistakes.

Problem	Cause	Fix
Installed Stable Diffusion but it does not run	Not enough GPU memory, complex setup	Practice on an online service first, then review your PC
Cannot pin down precise shapes in NovelAI	Features are within a fixed range	Describe the pose more specifically, consider Stable Diffusion if needed
A prompt brought over does not work	Different emphasis syntax	Convert the emphasis marks to each tool's syntax
Costs more than expected	Plans or electricity not considered	Decide how many images you will make, then compare

FAQ

Frequently Asked Questions

Which looks better, NovelAI or Stable Diffusion?

It depends on the model and settings, so there is no single answer. NovelAI gives consistent anime pictures from the start, while Stable Diffusion can be tuned to your taste through model choice and adjustment.

Can I use NovelAI prompts in Stable Diffusion?

The Danbooru tag parts usually work as they are. Convert emphasis marks such as { } into Stable Diffusion's (tag:1.2) form.

Is Stable Diffusion free?

Much of the software is free, but you need a PC with a GPU and pay for electricity. If you run it on an online service, that service's fees apply.

Which should beginners start with?

If you do not want to set up a PC, start with a service such as NovelAI; if you have a PC with a GPU and like researching, start with Stable Diffusion.