What does CFG scale actually do?

CFG (classifier-free guidance) scale controls how strongly the model is pushed toward your prompt versus its own learned priors. Low values let the model wander and stay creative; high values force literal prompt adherence but can oversaturate or distort.

What is a good default CFG scale?

For SD 1.5 the common sweet spot is 6–9, and for SDXL it is roughly 5–8. Turbo, Lightning and LCM models are tuned for very low guidance, usually 1–2.

Why does a high CFG scale burn the image?

Pushing guidance too high overshoots the prompt and amplifies contrast and saturation until the image looks fried, with halos and blown highlights. If that happens, lower CFG or raise the step count.

Is anything sent to a server?

No. The advisor is fully client-side. Your selections never leave your browser and no image is generated here.

SD CFG Scale Advisor

Stable Diffusion CFG scale advisor

CFG scale is the dial that decides whether Stable Diffusion obeys your prompt literally or interprets it loosely. Set it too low and the model ignores you; too high and the image burns. Pick your model and prompt style and this advisor shows a recommended range, then explains exactly what each value on the 1–30 slider does.

How CFG scale works

CFG stands for classifier-free guidance. At each denoising step the model makes two predictions — one conditioned on your prompt and one unconditioned — and CFG scale controls how far it pushes toward the conditioned one:

CFG 1–2    barely guided — creative, can ignore the prompt (turbo/LCM models)
CFG 5–8    balanced — follows the prompt while keeping natural detail
CFG 9–12   strong adherence — literal, higher contrast
CFG 13+    overshoot — oversaturated, "fried", halos, distortion

Different model families are tuned for different ranges. Turbo, Lightning and LCM checkpoints are distilled to work at very low guidance (1–2). Standard SD 1.5 likes 6–9, while SDXL is happiest a little lower at 5–8.

Tips for tuning CFG

Start at the model default, then move in steps of 1.
Long, detailed prompts need less CFG — the prompt already constrains the image. Short prompts can take more.
Fried image? Lower CFG before anything else, or add a few steps.
Ignoring your prompt? Raise CFG, but check your prompt order and weighting first — that often fixes adherence without the saturation cost.