Black Forest Labs
FLUX.2 [klein] 4B
FLUX.2 [klein] 4B is the smallest FLUX.2 model from Black Forest Labs, served through OpenRouter. At 25 credits an image it is the cheapest way to try FLUX.2 on a prompt, and it still accepts up to four reference photos at no extra cost.
FLUX.2 [klein] 4B is made by Black Forest Labs. Prompt Generator is independent and not affiliated with Black Forest Labs; we run the model through OpenRouter.
25 credits
- Model
- FLUX.2 [klein] 4B · Black Forest Labs
- Cost
- 25 credits
Your results appear here when you press Generate.
Specs
- Vendor
- Black Forest Labs
- Type
- Text to image
- Price
- 25 credits per image
- Aspect ratios
- 1:1, 4:3, 3:4, 16:9, 9:16
- Reference images
- up to 4
- Served via
- OpenRouter
Best for
- Drafts and quick tests
- Generating many options on a budget
- Checking a prompt before FLUX.2 [pro] or [max]
Tips
- Iterate here, then send the prompt that works to FLUX.2 [pro] (50 credits) or [max] (110).
- Keep prompts short and concrete; small models do best with one clear subject.
Tools that use FLUX.2 [klein] 4B
Questions
1How many credits does FLUX.2 [klein] 4B use?
25 credits per image, one image per run. Reference photos cost nothing extra. If a run fails, the credits go back to your balance; runs stopped by the model's safety filter are refunded up to 10 times a day.
2What can I give FLUX.2 [klein] 4B besides a prompt?
Up to 4 reference photos (PNG, JPEG or WebP, up to 12 MB each). Leave them out and pick Create image to work from the prompt alone, or add them and pick Edit photo. Output sizes: 1:1, 4:3, 3:4, 16:9 or 9:16.
3Can I use what I make with FLUX.2 [klein] 4B in paid work?
Yes, when you made it on a paid plan or after buying credits. Results made only with the free sign-up credits are for personal, non-commercial use. Anything you upload must be yours to use, and people shown in it must have agreed.
Compare with all models.