How to train a FLUX.2 klein LoRA: trainers, VRAM and settings

Everything you need to train FLUX.2 klein (4B) LoRAs: which trainers support it, VRAM, settings and where to rent a GPU.

Trainer support

Trainer	Status
ai-toolkit	supported (klein base 4B and 9B)
OneTrainer	supported
musubi-tuner	supported
kohya sd-scripts	unknown
SimpleTuner	unknown (Flux.2 listed; variant not stated)

VRAM

12-16 GB

→ Train FLUX.2 klein on 12 GB

→ Train FLUX.2 klein on 16 GB

Settings that work

diffusers v0.42.0 (Oct 23, PR #14163) loads LoKr adapters for FLUX.2 and FLUX.2 klein
ComfyUI master (PR #17196) runs the FLUX.2 VAE in fp16: faster, closer to fp32, and no tiled VAE node needed at high resolutions. Your existing VAE file works after updating; don't use bf16 FLUX.2 VAE files

Full guide with recipes: How to train a FLUX.2 klein LoRA.

Trainer comparisons

Where to rent a 16 GB+ GPU

Cheapest 16 GB+ cards (2026-10-20 08:06 UTC) from RunPod and Vast.ai. Prices move constantly; see the live price table.

GPU	VRAM	RunPod community $/hr	Vast.ai cheapest $/hr
Tesla V100	16 GB	$0.19	$0.08
RTX 3090	24 GB	$0.22	$0.12
RTX 5060 Ti	16 GB	—	$0.14
Tesla V100S	32 GB	—	$0.14
RTX A5000	24 GB	$0.16	—
RTX A4000	16 GB	$0.17	—

Sources

FAQ

Which trainers support FLUX.2 klein?

ai-toolkit, OneTrainer, musubi-tuner

How much VRAM does FLUX.2 klein LoRA training need?

12-16 GB

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Data updated 2026-10-20. Disclosure: RunPod and Vast.ai links are referral links; ImageLoRA may earn a commission at no cost to you. unknown = no data yet. · Raw data (JSON) · llms.txt