FLUX.2 Flexvs.Stable Image Ultra
Which one is better?
We have not tested Stable Image Ultra ourselves yet. Stable Image Ultra has no arena rating yet. Stable Image Ultra has no API price.
Same prompt, two images
Same task, the first image of each.
No image from the four fixed tasks for Stable Image Ultra yet.This model does not yet have a complete GraduallyBench run.
Result for “Typography and layout”:only FLUX.2 Flex tested
What the rating looks at: Legible text, hierarchy, and composition.
“Ahead”: better in all three rating rounds. “Slightly ahead”: a higher value, but not in every round.
Missing image run for Stable Image Ultra
This model does not yet have a complete GraduallyBench run. Run the missing fixed tasks, archive the first output of each, and evaluate them blind.
DocumentationThe numbers at a glance
FLUX.2 Flex
Rank 17 of 22
Stable Image Ultra
not in the arena
FLUX.2 Flex
Rank 35 of 74
Stable Image Ultra
not tested yet
FLUX.2 Flex
fairly cheap
Stable Image Ultra
no API price
Ranks among the 22 image models with an arena rating and the 74 with a GraduallyBench run; prices compared with 28 models with an API price.
FLUX.2 Flex
- Subscription
- No Black Forest Labs subscription includes this model. Through other providers from €6.83 a month (Poe Basic, with limited points). 26 plans in Germany.
- Via API
- $0.06 per image, 100 images $6.
Stable Image Ultra
- Subscription
- n/a No plan in Germany names exactly this model.
- Via API
- No API price known. Access: API.
- Weights
- unknown.
Subscriptions only count plans that name exactly this model. Subscription prices include VAT, API prices are in dollars.
Arena rating (LMArena) from Oct 28, 2026 · GraduallyBench from Nov 1, 2026 · API prices from Oct 28, 2026 · Subscription database from Sep 29, 2026 (34 days old)
All data side by side
The better value is bold. For ratings only when the gap is clear.
| Kennzahl | FLUX.2 Flex | Stable Image Ultra |
|---|---|---|
| Ratings | ||
| Arena ratingfrom votes by users, higher is better | 1,156 | n/a |
| Arena rank | Rank 17 of 22 | n/a |
| Arena votesmore votes, a safer rating | 156,876 | n/a |
| GraduallyBenchour own rating, 0 to 100 | 57 | n/a |
| GraduallyBench by task | ||
| Typography and layoutLegible text, hierarchy, and composition | 71 | n/a |
| Product photographyMaterials, reflections, and fine details | 56 | n/a |
| Character and detailAnatomy, clothing, and spatial consistency | 58 | n/a |
| InfographicNumbers, labels, and visual organization | 41 | n/a |
| API price | ||
| Per imagelower is better | $0.06 | n/a |
| 100 images | $6 | n/a |
| Profile | ||
| Released | November 2025 | n/a |
| Weightsopen means: runs locally | proprietary | unknown |
| Lifecycle | no notice | Current API generation service based on Stable Diffusion 3.5 Large, not an independent checkpoint |
| Access | API, Web app | API |
| Parameters | not published | not published |
| Largest output | 4 Megapixel | not consistently published |
| Plans in Germanynaming exactly this model | 26 | n/a |
API prices for one image at 1,024 × 1,024 pixels according to Artificial Analysis.
Sources: FLUX.2 Flex model source (verified Sep 24, 2026) · Stable Image Ultra model source, status source (verified Nov 1, 2026)
Arena ratings by category
From blind votes on LMArena. “Ahead” means the lead is clear.
No shared arena score in the stored snapshot
The stored benchmark database contains no measurement for FLUX.2 Flex and Stable Image Ultra from the same arena and category. Older model versions are not used as substitutes.
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