Image model comparison

FLUX.2 [klein] 4B vs FLUX.2 [pro]

Black Forest Labs' FLUX.2 [klein] 4B and Black Forest Labs' FLUX.2 [pro], side by side: price per image, image sizes, editing and aspect ratios — and when to choose which. Both run on one Cheaper Gen. API key.

Black Forest Labs

Up to −95%

FLUX.2[klein] 4B

FLUX.2 [klein] 4B

The fastest FLUX.2 — open weights, sub-second, a fraction of a cent

from

$0.0007/image

Black Forest Labs

Up to −36%

FLUX.2[pro]

FLUX.2 [pro]

Black Forest Labs' production image model — photoreal, fast, up to 4 MP

from

$0.0264/image

Price

FLUX.2 [klein] 4B vs FLUX.2 [pro]: price per image

Live prices at the tiers both models offer. Official list prices are on each model's pricing page.

FLUX.2 [klein] 4B and FLUX.2 [pro] prices at shared tiers
Tier	FLUX.2 [klein] 4B	FLUX.2 [pro]	Cheaper
1K	$0.0007/image 1K	$0.0264/image 1 MP	FLUX.2 [klein] 4B −97%
2K	$0.0027/image 2K	$0.066/image 4 MP	FLUX.2 [klein] 4B −96%

FLUX.2 [klein] 4B pricing →Cheap FLUX.2 [klein] 4B API →FLUX.2 [pro] pricing →Cheap FLUX.2 [pro] API →

Specs

Side-by-side specifications

From each model's API parameters in our catalog.

FLUX.2 [klein] 4B vs FLUX.2 [pro] specifications
Spec	FLUX.2 [klein] 4B	FLUX.2 [pro]
Developer	Black Forest Labs	Black Forest Labs
Released	Jan 15, 2026	Nov 25, 2025
Tasks	Text to image, Image editing	Text to image, Image editing
Sizes	1K · 2K	1 MP · 2 MP · 3 MP · 4 MP
Edit inputs	Up to 4 images	Up to 8 images
Quality levels	—	—
Aspect ratios	7 (1:1, 4:3, 3:4, 16:9, 9:16, 3:2…)	10 (1:1, 4:3, 3:4, 16:9, 9:16, 3:2…)
Starting price	$0.0007/image (1K)	$0.0264/image (1 MP)
Below official price	up to 95%	up to 36%

Verdict

When to choose which

Each point below comes from the price and spec data above.

Choose FLUX.2 [klein] 4B for

Lower price: $0.0007/image vs $0.0264/image at 1K (97% less).
Higher maximum resolution: 2K vs 4 MP.
Newer model (released January 15, 2026).

FLUX.2 [klein] 4B at a glance

Sub-second — 4-step distilled
Fraction of a cent — Per 1 MP image
4 references — Image editing
Open weights — Apache-2.0

Choose FLUX.2 [pro] for

Edits with up to 8 input images (vs 4).
More aspect ratios: 10 vs 7.

FLUX.2 [pro] at a glance

Up to 4 MP — 1–4 megapixel output
Clean text — Logos and labels
Fast — Seconds per image
Per-MP pricing — Pay for the size you need

Try both with the same prompt

Same API key and balance; only the endpoint changes. Failed generations are refunded.

POST /api/v1/run/bfl/flux-2-klein-4b/text-to-image
POST /api/v1/run/bfl/flux-2-pro/text-to-image

FLUX.2 [klein] 4B in Studio FLUX.2 [pro] in Studio

FAQ

FLUX.2 [klein] 4B vs FLUX.2 [pro] questions

FLUX.2 [klein] 4B is cheaper at 2 of 2 shared tiers. 1K: FLUX.2 [klein] 4B $0.0007/image, FLUX.2 [pro] $0.0264/image; 2K: FLUX.2 [klein] 4B $0.0027/image, FLUX.2 [pro] $0.066/image. Prices are live and billed per image.

FLUX.2 [klein] 4B: up to 2K, edits with up to 4 input images. FLUX.2 [pro]: up to 4 MP, edits with up to 8 input images.

Yes. Both run through the same Cheaper Gen. API and balance: POST /v1/run/{endpoint} with the model's endpoint id, then poll or receive a webhook. Switching models means changing the endpoint and its input fields — no new account or SDK.

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FLUX.2 [klein] 4B is developed by Black Forest Labs; FLUX.2 [pro] by Black Forest Labs. Cheaper Gen. provides API access to both through official upstream endpoints and does not own either model. Trademarks belong to their respective owners.