FLUX.2 Klein 9Bvs.FLUX.2 Klein 4B

Which one is better?

In our own test, FLUX.2 Klein 9B leads. FLUX.2 Klein 4B has no arena rating yet. FLUX.2 Klein 4B has no API price.

Same task, the first image of each. The task with the biggest difference is preselected.

FLUX.2 Klein 9B: Product photography, first image from the fixed test run — FLUX.2 Klein 9B72 out of 100

FLUX.2 Klein 4B: Product photography, first image from the fixed test run — FLUX.2 Klein 4B54 out of 100

Result for “Product photography”:FLUX.2 Klein 9B slightly ahead

Prompt given to both modelsCreate a square premium product photograph of a brushed titanium wristwatch standing upright on dark green marble. The watch has a cream dial, thin black hands set to 10:10, twelve distinct hour markers, a realistic crown, and a dark brown leather strap. Soft window light from the left, controlled reflections, shallow depth of field, no text, no logo, no extra objects.

What the rating looks at: Materials, reflections, and fine details.

“Ahead”: better in all three rating rounds. “Slightly ahead”: a higher value, but not in every round.

Test protocol of the images

Both models receive the same archived prompt in exactly one request, and the first result counts. Files are normalized to 1,024 × 1,024 pixels without cropping. Provider resolution, randomness, quality tier and prompt processing can still differ. The images are a practical visual test, not a reconstruction of the arena configuration.

Character and detail

FLUX.2 Klein 9B: fal, requested 1024x1024, n=1, seed=1587849924, estimated cost $0.006291, generated Aug 14, 2026, 1:52 PM. Source

FLUX.2 Klein 4B: fal, requested 1024x1024, n=1, seed=707400387, Fal's published 4B text-to-image endpoint; default four inference steps, estimated cost $0.005000, generated Nov 1, 2026, 9:01 PM. Source

Protocol gradually-image-comparison-v1. Prompt SHA 256: 985a75b38642a9f0e5e0c0e0c67f1b7f67780d42bd2168fa24e9a7a7a94b0da6

FLUX.2 Klein 9B image SHA 256: 84eceab680e59de6b9d4e68b3c21f6515ce093ff7d110992049e847570dd565f

FLUX.2 Klein 4B image SHA 256: 170cebb7cf75bc033a92371199812674f9cfa9641d5e9fb13947ccf892d4ed53

Infographic

FLUX.2 Klein 9B: fal, requested 1024x1024, n=1, seed=1082231541, estimated cost $0.006291, generated Aug 14, 2026, 1:52 PM. Source

FLUX.2 Klein 4B: fal, requested 1024x1024, n=1, seed=290140178, Fal's published 4B text-to-image endpoint; default four inference steps, estimated cost $0.005000, generated Nov 1, 2026, 9:01 PM. Source

Protocol gradually-image-comparison-v1. Prompt SHA 256: ed65cb4e6a51e2336f8b149ad4cbb16e020f07d527ad94362e719d2dcf91d94f

FLUX.2 Klein 9B image SHA 256: 1d2eb263ca5a25794a88df7bb04f5c13e10ed9a289371d1dcc7ed6d6e0a297e2

FLUX.2 Klein 4B image SHA 256: 42b729a5a72207b5a92464f3ecf1713459ab1b105c3041c14b75c7622630015e

Product photography

FLUX.2 Klein 9B: fal, requested 1024x1024, n=1, seed=1388538280, estimated cost $0.006291, generated Aug 14, 2026, 1:39 PM. Source

FLUX.2 Klein 4B: fal, requested 1024x1024, n=1, seed=1254275381, Fal's published 4B text-to-image endpoint; default four inference steps, estimated cost $0.005000, generated Nov 1, 2026, 9:00 PM. Source

Protocol gradually-image-comparison-v1. Prompt SHA 256: c67fd71e91304458a2feef5c91efa8677260fab0c0099a29a2c52cb579f5b2f3

FLUX.2 Klein 9B image SHA 256: e7208f19ccfb9b810b9648cb1861797b7155ad91933d1660059236cef413ebe0

FLUX.2 Klein 4B image SHA 256: 8fae4a7f6abb7467281c439dc93aa656031626f88c8a54f95f49850cbf045580

Typography and layout

FLUX.2 Klein 9B: fal, requested 1024x1024, n=1, seed=1340991019, estimated cost $0.006291, generated Aug 14, 2026, 2:41 PM. Source

FLUX.2 Klein 4B: fal, requested 1024x1024, n=1, seed=1270698692, Fal's published 4B text-to-image endpoint; default four inference steps, estimated cost $0.005000, generated Nov 1, 2026, 9:00 PM. Source

Protocol gradually-image-comparison-v1. Prompt SHA 256: 2e012c3d14ee5dd02203a94f394ca80a5038cdebd6032b25a8b8a221f2255419

FLUX.2 Klein 9B image SHA 256: c5f23870e70f2245d24a3689f2579ceb770e5edf8c3c89b7d6ed7ae138f262f6

FLUX.2 Klein 4B image SHA 256: 7c2c3e30c20c98e90033087b2b95b151bddc3252dd4aed7092fcbca4ae4ea96e

The numbers at a glance

Arena ratingfrom votes by users · higher is better

1,070

FLUX.2 Klein 9B

Rank 21 of 22

n/a

FLUX.2 Klein 4B

not in the arena

GraduallyBenchour own rating, 0 to 100 · higher is better

FLUX.2 Klein 9B

Rank 50 of 74

FLUX.2 Klein 4B

Rank 55 of 74

Price per imagedollars through the API · lower is better

$0.015

FLUX.2 Klein 9B

cheap

n/a

FLUX.2 Klein 4B

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 Klein 9B

Subscription: n/a No plan in Germany names exactly this model.
Via API: $0.015 per image, 100 images $1.50.
License: Open weights, Weights released under the FLUX Non-Commercial License.

FLUX.2 Klein 4B

Subscription: No Black Forest Labs subscription includes this model. Through other providers from €6.83 a month (Poe Basic, with limited points). 12 plans in Germany.
Via API: No API price known. Access: API, local.
License: Open weights.

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 Klein 9B	FLUX.2 Klein 4B
Ratings
Arena ratingfrom votes by users, higher is better	1,070	n/a
Arena rank	Rank 21 of 22	n/a
Arena votesmore votes, a safer rating	150,695	n/a
GraduallyBenchour own rating, 0 to 100	45	37
GraduallyBench by task
Typography and layoutLegible text, hierarchy, and composition	22	21
Product photographyMaterials, reflections, and fine details	72	54
Character and detailAnatomy, clothing, and spatial consistency	59	53
InfographicNumbers, labels, and visual organization	26	19
API price
Per imagelower is better	$0.015	n/a
100 images	$1.50	n/a
Profile
Released	January 2026	n/a
Weightsopen means: runs locally	openWeights released under the FLUX Non-Commercial License	open
Access	API, local	API, local
Parameters	9 billion	4 billion
Largest output	4 Megapixel	not consistently published
Plans in Germanynaming exactly this model	n/a	12

API prices for one image at 1,024 × 1,024 pixels according to Artificial Analysis.

Sources: FLUX.2 Klein 9B model source, status source (verified Sep 24, 2026) · FLUX.2 Klein 4B model 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 Klein 9B and FLUX.2 Klein 4B from the same arena and category. Older model versions are not used as substitutes.

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More matchups

Compare FLUX.2 Klein 9B and FLUX.2 Klein 4B with other important image models.

View the complete image model comparison

Same prompt, two images

The numbers at a glance

FLUX.2 Klein 9B

FLUX.2 Klein 4B

All data side by side

Arena ratings by category

No shared arena score in the stored snapshot

Compare another matchup

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