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FLUX.2 Klein 4Bvs.Sana-Sprint 0.6B 1024px

Which one is better?

In our own test, FLUX.2 Klein 4B leads. Neither is in the arena. Neither has an API price.

Same prompt, two images

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

FLUX.2 Klein 4B: Character and detail, first image from the fixed test run
FLUX.2 Klein 4B53 out of 100
Sana-Sprint 0.6B 1024px: Character and detail, first image from the fixed test run
Sana-Sprint 0.6B 1024px6 out of 100

Result for “Character and detail”:FLUX.2 Klein 4B ahead

Prompt given to both modelsCreate 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.

What the rating looks at: Anatomy, clothing, and spatial consistency.

“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 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

Sana-Sprint 0.6B 1024px: manual, 1:1, one request, first output, one image, provider-side randomize seed enabled, observed seed 1646387073, native 1024x1024, 2 inference steps, guidance 4.5, no prompt enhancement, no reference images, exact checkpoint Efficient-Large-Model/Sana_Sprint_0.6B_1024px_diffusers, Space commit b42328123ed688df4bee46e52c60cc1dc62c045a, generated Nov 1, 2026, 9:42 PM. Source

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

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

Sana-Sprint 0.6B 1024px image SHA 256: 17356f29ad7fa9644e9683ec624d0c01ad56ff0c14d078db5f78f3b6bcf6a45e

Infographic

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

Sana-Sprint 0.6B 1024px: manual, 1:1, one request, first output, one image, provider-side randomize seed enabled, observed seed 1798448399, native 1024x1024, 2 inference steps, guidance 4.5, no prompt enhancement, no reference images, exact checkpoint Efficient-Large-Model/Sana_Sprint_0.6B_1024px_diffusers, Space commit b42328123ed688df4bee46e52c60cc1dc62c045a, generated Nov 1, 2026, 9:42 PM. Source

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

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

Sana-Sprint 0.6B 1024px image SHA 256: efbab43ef1980109bff4084afe6162c4915e4fb55185617adaac5713f20b5e24

Product photography

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

Sana-Sprint 0.6B 1024px: manual, 1:1, one request, first output, one image, provider-side randomize seed enabled, observed seed 520567323, native 1024x1024, 2 inference steps, guidance 4.5, no prompt enhancement, no reference images, exact checkpoint Efficient-Large-Model/Sana_Sprint_0.6B_1024px_diffusers, Space commit b42328123ed688df4bee46e52c60cc1dc62c045a, generated Nov 1, 2026, 9:42 PM. Source

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

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

Sana-Sprint 0.6B 1024px image SHA 256: ac2d880a5b40924b518e25c61c5e077ffc9c5825f3eb896d733096ac6c631e46

Typography and layout

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

Sana-Sprint 0.6B 1024px: manual, 1:1, one request, first output, one image, provider-side randomize seed enabled, observed seed 1229099615, native 1024x1024, 2 inference steps, guidance 4.5, no prompt enhancement, no reference images, exact checkpoint Efficient-Large-Model/Sana_Sprint_0.6B_1024px_diffusers, Space commit b42328123ed688df4bee46e52c60cc1dc62c045a, generated Nov 1, 2026, 9:42 PM. Source

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

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

Sana-Sprint 0.6B 1024px image SHA 256: fd10095819c7746d6b52cc50e3d63f9d81eff271ad1edb4d3ba667a954098ac7

The numbers at a glance

Arena ratingfrom votes by users · higher is better
n/a

FLUX.2 Klein 4B

not in the arena

n/a

Sana-Sprint 0.6B 1024px

not in the arena

GraduallyBenchour own rating, 0 to 100 · higher is better
37

FLUX.2 Klein 4B

Rank 55 of 74

5

Sana-Sprint 0.6B 1024px

Rank 73 of 74

Price per imagedollars through the API · lower is better
n/a

FLUX.2 Klein 4B

no API price

n/a

Sana-Sprint 0.6B 1024px

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 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.

Sana-Sprint 0.6B 1024px

Subscription
n/a No plan in Germany names exactly this model.
Via API
No API price known. Access: local.
License
Open weights.

Subscriptions only count plans that name exactly this model. Subscription prices include VAT, API prices are in dollars.

GraduallyBench from Nov 1, 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.

KennzahlFLUX.2 Klein 4BSana-Sprint 0.6B 1024px
Ratings
Arena ratingfrom votes by users, higher is bettern/an/a
Arena rankn/an/a
Arena votesmore votes, a safer ratingn/an/a
GraduallyBenchour own rating, 0 to 100375
GraduallyBench by task
Typography and layoutLegible text, hierarchy, and composition212
Product photographyMaterials, reflections, and fine details548
Character and detailAnatomy, clothing, and spatial consistency536
InfographicNumbers, labels, and visual organization194
API price
Per imagelower is bettern/an/a
100 imagesn/an/a
Profile
Releasedn/aMar 22, 2025
Weightsopen means: runs locallyopenopen
AccessAPI, locallocal
Parameters4 billion0.6 billion
Largest outputnot consistently publishednot consistently published
Plans in Germanynaming exactly this model12n/a

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

Sources: FLUX.2 Klein 4B model source (verified Nov 1, 2026) · Sana-Sprint 0.6B 1024px 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 4B and Sana-Sprint 0.6B 1024px from the same arena and category. Older model versions are not used as substitutes.

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