Head-to-head comparison

FLUX.2 Flex vs. FLUX.2 Klein 9B

Compare shared capability tests, arena scores with documented retrieval dates, task-specific image pricing, and verified specifications. Research benchmarks, preference arenas, and our n = 1 samples remain separate.

shared result series: 16
shared sample prompts: 4
latest arena retrieval: 2026-08-26

First image modelSecond image model

Specifications and cost

General specifications and task-specific pricing

A model can have one price for generating new images and another for editing. Prices therefore remain tied to the corresponding arena configuration.

Specifications and pricing for FLUX.2 Flex and FLUX.2 Klein 9B
Attribute	FLUX.2 Flex	FLUX.2 Klein 9B
Provider	Black Forest Labs	Black Forest Labs
Released	November 2025	January 2026
Access	API, Web app	API, local
Lifecycle	No separate lifecycle notice	No separate lifecycle notice
Weights	Proprietary	Open weights
Parameters	Not published	9 billion
Maximum output	4 Megapixel	4 Megapixel
Arena configuration	Flex	9B
Text-to-image price	$60 per 1,000 images	$15 per 1,000 images
Editing price	$120 per 1,000 images	$17 per 1,000 images
Technical source	Model sourceVerified 2026-08-15	Model sourceVerified 2026-08-15

FLUX.2 FlexFLUX.2 Klein 9B

Text to Image ArenaUSD per 1,000 images at 1,024 × 1,024 pixels

FLUX.2 Flex$60

FLUX.2 Klein 9B$15

Image Editing ArenaUSD per 1,000 images at 1,024 × 1,024 pixels

FLUX.2 Flex$120

FLUX.2 Klein 9B$17

Key to the marks:better valuebetter, but not conclusivetie

Prompt adherence and specialist tests

Shared capability benchmarks

Every matchup includes the same four Gradually sample tasks. For each task, one archived first output from every model is ranked in three differently ordered, model-blind passes. The published 0-100 value normalizes the mean rank. It must still be read as an n = 1 sample per model. No exact shared result from the integrated research benchmarks is available for this pair.

FLUX.2 FlexFLUX.2 Klein 9B

Gradually sample test: Typography and layoutMean of three blind ranks across all 28 first outputs, n = 1 each

FLUX.2 Flex76.6 / 100

FLUX.2 Klein 9B9.9 / 100

Gradually sample test: Product photographyMean of three blind ranks across all 28 first outputs, n = 1 each

FLUX.2 Flex46.9 / 100

FLUX.2 Klein 9B75.3 / 100

Gradually sample test: Character and detailMean of three blind ranks across all 28 first outputs, n = 1 each

FLUX.2 Flex39.5 / 100

FLUX.2 Klein 9B43.2 / 100

Gradually sample test: InfographicMean of three blind ranks across all 28 first outputs, n = 1 each

FLUX.2 Flex25.9 / 100

FLUX.2 Klein 9B12.3 / 100

Key to the marks:better valuebetter, but not conclusivetie

Capability benchmark scores for FLUX.2 Flex and FLUX.2 Klein 9B
Benchmark	FLUX.2 Flex	FLUX.2 Klein 9B
Gradually sample test: Typography and layout	Higher blind-rank score76.6 / 100 Mean rank: 7.33 (6 / 10 / 6) Five rubric scores Headline: 1.67 / 2 Subline: 1.67 / 2 Text control: 1.67 / 2 Visual brief: 1.33 / 2 Layout: 1 / 2	9.9 / 100 Mean rank: 25.33 (25 / 26 / 25) Five rubric scores Headline: 1.67 / 2 Subline: 0.67 / 2 Text control: 1 / 2 Visual brief: 1.33 / 2 Layout: 1 / 2
Gradually sample test: Product photography	46.9 / 100 Mean rank: 15.33 (12 / 19 / 15) Five rubric scores Subject: 1.33 / 2 Time: 1.33 / 2 Watch details: 1.33 / 2 Photography: 1.33 / 2 Exclusions: 1.33 / 2	Higher blind-rank score75.3 / 100 Mean rank: 7.67 (10 / 6 / 7) Five rubric scores Subject: 1.33 / 2 Time: 1.33 / 2 Watch details: 1.33 / 2 Photography: 1.33 / 2 Exclusions: 1.33 / 2
Gradually sample test: Character and detail	39.5 / 100 Mean rank: 17.33 (27 / 7 / 18) Five rubric scores Scene: 1.33 / 2 Wardrobe: 1.33 / 2 Anatomy: 1.33 / 2 Props: 1 / 2 Environment: 1 / 2	Higher blind-rank score43.2 / 100 Mean rank: 16.33 (4 / 25 / 20) Five rubric scores Scene: 1.33 / 2 Wardrobe: 1.33 / 2 Anatomy: 1 / 2 Props: 0.33 / 2 Environment: 1 / 2
Gradually sample test: Infographic	Higher blind-rank score25.9 / 100 Mean rank: 21 (21 / 19 / 23) Five rubric scores Title: 1.67 / 2 Sequence: 1 / 2 Labels: 1 / 2 Diagram: 1 / 2 Clarity: 1 / 2	12.3 / 100 Mean rank: 24.67 (25 / 24 / 25) Five rubric scores Title: 1.67 / 2 Sequence: 1.33 / 2 Labels: 0.33 / 2 Diagram: 0.33 / 2 Clarity: 0.67 / 2
Key to the marks:better valuebetter, but not conclusivetie

Independent preference tests

Shared arena benchmarks

Artificial Analysis and Arena derive scores from blind comparisons. Raters see outputs for the same prompt and choose the image they prefer. Separate series cover text rendering, photorealism, portraits, art, commercial design, and image editing. Confidence intervals indicate how certain a measured lead is.

12 shared result series

FLUX.2 FlexFLUX.2 Klein 9B

Text to Image ArenaBlind preference from the same prompt, higher is better

FLUX.2 Flex1,224 Elo

FLUX.2 Klein 9B1,144 Elo

Image Editing ArenaBlind preference from the same prompt, higher is better

FLUX.2 Flex1,162 Elo

FLUX.2 Klein 9B1,166 Elo

LMArena Text to Image: 3D modelingBlind preference from the same prompt, higher is better

FLUX.2 Flex1,171.967

FLUX.2 Klein 9B1,078.396

LMArena Text to Image: ArtBlind preference from the same prompt, higher is better

FLUX.2 Flex1,155.954

FLUX.2 Klein 9B1,078.844

LMArena Text to Image: CartoonBlind preference from the same prompt, higher is better

FLUX.2 Flex1,162.335

FLUX.2 Klein 9B1,063.975

LMArena Text to Image: Commercial designBlind preference from the same prompt, higher is better

FLUX.2 Flex1,173.137

FLUX.2 Klein 9B1,069.649

LMArena Text to Image: OverallBlind preference from the same prompt, higher is better

FLUX.2 Flex1,156.466

FLUX.2 Klein 9B1,069.517

LMArena Text to Image: PhotorealismBlind preference from the same prompt, higher is better

FLUX.2 Flex1,146.683

FLUX.2 Klein 9B1,090.118

LMArena Text to Image: PortraitsBlind preference from the same prompt, higher is better

FLUX.2 Flex1,144.533

FLUX.2 Klein 9B1,092.062

LMArena Text to Image: Text renderingBlind preference from the same prompt, higher is better

FLUX.2 Flex1,172.004

FLUX.2 Klein 9B1,057.362

LMArena Image Editing: Multi-image editingBlind preference from the same prompt, higher is better

FLUX.2 Flex1,233.804

FLUX.2 Klein 9B1,212.545

LMArena Image Editing: OverallBlind preference from the same prompt, higher is better

FLUX.2 Flex1,225.217

FLUX.2 Klein 9B1,224.398

Key to the marks:better valuebetter, but not conclusivetie

Arena benchmark scores for FLUX.2 Flex and FLUX.2 Klein 9B
Benchmark	FLUX.2 Flex	FLUX.2 Klein 9B	Source
Text to Image Arena	Higher score1,224 Elo Rank 19, 95% confidence interval: ±10, 5,047 ratings	1,144 Elo Rank 67, 95% confidence interval: ±9, 9,077 ratings	Artificial AnalysisRetrieved 2026-08-26
Image Editing Arena	1,162 Elo Rank 37, 95% confidence interval: ±7, 7,847 ratings	No clear lead1,166 Elo Rank 34, 95% confidence interval: ±7, 11,256 ratings	Artificial AnalysisRetrieved 2026-08-26
LMArena Text to Image: 3D modeling	Higher score1,171.967 Rank 19, 95% confidence interval: ±7.03, 15,066 ratings	1,078.396 Rank 54, 95% confidence interval: ±6.95, 13,814 ratings	LMArenaRetrieved 2026-08-26
LMArena Text to Image: Art	Higher score1,155.954 Rank 28, 95% confidence interval: ±6.38, 21,779 ratings	1,078.844 Rank 53, 95% confidence interval: ±6.28, 19,055 ratings	LMArenaRetrieved 2026-08-26
LMArena Text to Image: Cartoon	Higher score1,162.335 Rank 26, 95% confidence interval: ±5.15, 55,850 ratings	1,063.975 Rank 55, 95% confidence interval: ±5.01, 53,034 ratings	LMArenaRetrieved 2026-08-26
LMArena Text to Image: Commercial design	Higher score1,173.137 Rank 21, 95% confidence interval: ±4.95, 55,246 ratings	1,069.649 Rank 56, 95% confidence interval: ±4.59, 55,183 ratings	LMArenaRetrieved 2026-08-26
LMArena Text to Image: Overall	Higher score1,156.466 Rank 25, 95% confidence interval: ±3.42, 149,402 ratings	1,069.517 Rank 55, 95% confidence interval: ±3.25, 142,762 ratings	LMArenaRetrieved 2026-08-26
LMArena Text to Image: Photorealism	Higher score1,146.683 Rank 33, 95% confidence interval: ±4.87, 63,801 ratings	1,090.118 Rank 54, 95% confidence interval: ±4.7, 60,335 ratings	LMArenaRetrieved 2026-08-26
LMArena Text to Image: Portraits	Higher score1,144.533 Rank 34, 95% confidence interval: ±5.82, 33,696 ratings	1,092.062 Rank 55, 95% confidence interval: ±5.73, 32,758 ratings	LMArenaRetrieved 2026-08-26
LMArena Text to Image: Text rendering	Higher score1,172.004 Rank 22, 95% confidence interval: ±5.14, 49,969 ratings	1,057.362 Rank 56, 95% confidence interval: ±4.77, 51,643 ratings	LMArenaRetrieved 2026-08-26
LMArena Image Editing: Multi-image editing	Higher score1,233.804 Rank 22, 95% confidence interval: ±4.38, 125,392 ratings	1,212.545 Rank 25, 95% confidence interval: ±4.03, 147,846 ratings	LMArenaRetrieved 2026-08-26
LMArena Image Editing: Overall	No clear lead1,225.217 Rank 35, 95% confidence interval: ±3.17, 415,933 ratings	1,224.398 Rank 37, 95% confidence interval: ±2.9, 507,321 ratings	LMArenaRetrieved 2026-08-26
Key to the marks:better valuebetter, but not conclusivetie

Visual comparison

Sample images

Our images complement preference data, but do not replace it. The prompt, request count, and selection rule match. Provider resolution, quality tier, randomness, and prompt processing remain visible limitations, so this is not a fully controlled laboratory test.

Largely standardized comparison protocol. Both models receive the same archived prompt, 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. These images are a practical visual test, not a reconstruction of the arena configuration.

Character and detail

Anatomy, clothing, and spatial consistency

Prompt and settings

Create a square cinematic full-body portrait of a fictional bicycle courier waiting under a transparent umbrella at a rainy tram stop in Hamburg at blue hour. She wears a mustard raincoat, navy trousers, red sneakers, a silver helmet, and carries a teal messenger bag. Keep both hands visible, render the bicycle correctly, use realistic wet-street reflections, and include no readable brand names.

FLUX.2 Flex. Provider Together, 1024x1024, n=1, seed=provider random, provider default steps, model ID black-forest-labs/FLUX.2-flex, generated Aug 14, 2026, 12:25 PM. Source
FLUX.2 Klein 9B. Provider fal.ai, requested 1024x1024, n=1, seed=1587849924, estimated cost $0.006291, model ID fal-ai/flux-2/klein/9b, generated Aug 14, 2026, 1:52 PM. Source

Protocol gradually-image-comparison-v1, selection rule: first result.

Prompt SHA 256: 985a75b38642a9f0e5e0c0e0c67f1b7f67780d42bd2168fa24e9a7a7a94b0da6

FLUX.2 Flex, image SHA 256: 43b43d5782192d7284de2b824dd1caaaa6b25032d22fc3f8565d438b137089f3

FLUX.2 Flex, request SHA 256: fe5b22589e6505017dc44f4729b1bb60b15820ba3673354d03a69c8b82831953

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

FLUX.2 Klein 9B, request SHA 256: 5d005ee24926d68b7d2299b8ecbe4e14919f652761f6de2568a043f2a6258da0

Infographic

Numbers, labels, and visual organization

Prompt and settings

Create a square German infographic titled SO FUNKTIONIERT PHOTOSYNTHESE. Show exactly four numbered steps in this order: 1 LICHT, 2 WASSER, 3 CO₂, 4 ZUCKER + SAUERSTOFF. Use a clean editorial science style with one plant cross-section, simple arrows, high contrast, legible labels, and no other text.

FLUX.2 Flex. Provider Together, 1024x1024, n=1, seed=provider random, provider default steps, model ID black-forest-labs/FLUX.2-flex, generated Aug 14, 2026, 12:25 PM. Source
FLUX.2 Klein 9B. Provider fal.ai, requested 1024x1024, n=1, seed=1082231541, estimated cost $0.006291, model ID fal-ai/flux-2/klein/9b, generated Aug 14, 2026, 1:52 PM. Source

Protocol gradually-image-comparison-v1, selection rule: first result.

Prompt SHA 256: ed65cb4e6a51e2336f8b149ad4cbb16e020f07d527ad94362e719d2dcf91d94f

FLUX.2 Flex, image SHA 256: 105f60cdeb71a27021ffff1ad3c0ad919df4e5c74ad83b4628fbd64a8d795a09

FLUX.2 Flex, request SHA 256: 11d4ec056332340dc822c82021ef10c6a6aa92de6e44dc931a90b7cbb6f14146

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

FLUX.2 Klein 9B, request SHA 256: 8b8014fc63f520d73ff57d3d8df5eae880097383167d44918b963f2830d09940

Product photography

Materials, reflections, and fine details

Prompt and settings

Create 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.

FLUX.2 Flex. Provider Together, 1024x1024, n=1, seed=provider random, provider default steps, model ID black-forest-labs/FLUX.2-flex, generated Aug 14, 2026, 12:25 PM. Source
FLUX.2 Klein 9B. Provider fal.ai, requested 1024x1024, n=1, seed=1388538280, estimated cost $0.006291, model ID fal-ai/flux-2/klein/9b, generated Aug 14, 2026, 1:39 PM. Source

Protocol gradually-image-comparison-v1, selection rule: first result.

Prompt SHA 256: c67fd71e91304458a2feef5c91efa8677260fab0c0099a29a2c52cb579f5b2f3

FLUX.2 Flex, image SHA 256: 9fef39b1500635ddbf78bcb8d3d9a68463ce952aa1fab89d12f6efe023907de7

FLUX.2 Flex, request SHA 256: 1c864c5e5d7f1e7008f15466fd0786f801ae94b17939b4f10de9a61c27766a59

FLUX.2 Klein 9B, image SHA 256: e7208f19ccfb9b810b9648cb1861797b7155ad91933d1660059236cef413ebe0

FLUX.2 Klein 9B, request SHA 256: 21e2c14d1b6315c30134e1390f531349608855d4ef1a87527e6d0ba57b2974ca

Typography and layout

Legible text, hierarchy, and composition

Prompt and settings

Create a square editorial poster for an imaginary night train called MONDFALTER. Show the exact German headline MONDFALTER and the exact subline BERLIN NACH LISSABON. Use a restrained midnight-blue and warm-cream palette, one stylized moth, strong Swiss-grid typography, generous negative space, and no additional words or logos.

FLUX.2 Flex. Provider Together, 1024x1024, n=1, seed=provider random, provider default steps, model ID black-forest-labs/FLUX.2-flex, generated Aug 14, 2026, 2:01 PM. Source
FLUX.2 Klein 9B. Provider fal.ai, requested 1024x1024, n=1, seed=1340991019, estimated cost $0.006291, model ID fal-ai/flux-2/klein/9b, generated Aug 14, 2026, 2:41 PM. Source

Protocol gradually-image-comparison-v1, selection rule: first result.

Prompt SHA 256: 2e012c3d14ee5dd02203a94f394ca80a5038cdebd6032b25a8b8a221f2255419

FLUX.2 Flex, image SHA 256: 324f87bf898593446a400abb43bd00eee015fa0a1dc160db0f864402fc0b38af

FLUX.2 Flex, request SHA 256: a0aa716f2a302bdfa59820d2e2c27cc56f730e8e2e4d5b64223d29a6979e1475

FLUX.2 Klein 9B, image SHA 256: c5f23870e70f2245d24a3689f2579ceb770e5edf8c3c89b7d6ed7ae138f262f6

FLUX.2 Klein 9B, request SHA 256: 530872e813e988ba95025956a3743c6111120af963d90b8970a8bf3eced5547b

How to read this comparison

An Elo score is not a verdict on creativity

A higher arena score means this specific configuration was preferred more often in blind comparisons.

Typography, character consistency, local execution, licensing, and price may matter more to your workload than overall visual appeal.

Prices cover 1,000 images at 1,024 × 1,024 pixels using settings documented by Artificial Analysis. Subscriptions and special rates are excluded.

More matchups

Compare FLUX.2 Flex and FLUX.2 Klein 9B with other important image models using the same benchmark and sample methodology.

View the complete image model comparison

FLUX.2 Flex vs. FLUX.2 Klein 9B

Change image model selection

General specifications and task-specific pricing

Shared capability benchmarks

Shared arena benchmarks

Sample images

Character and detail

Infographic

Product photography

Typography and layout

An Elo score is not a verdict on creativity

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