How much GPU memory does Gemma 4 12B need?
Google lists about 26.7 GB at BF16, 13.4 GB at SFP8, and 6.7 GB at Q4_0. The official BF16 files total 22.28 GiB before runtime and context state.
Gemma 4 / official memory worksheet
Google publishes one inference-memory table for the full Gemma 4 family. Use it as the loading baseline, then add context, concurrency, multimodal inputs, and runtime-specific reserve.
Open the editable Gemma 4 12B Q4 plan →Quick answer / official loading estimates
Google's values are approximate inference memory, not raw parameter arithmetic. The editable links preserve the published checkpoint or family estimate as the starting input so the runtime reserve stays visible.
Official Gemma 4 inference table
Google says the table includes approximately 20% overhead for model loading. Treat every value as a first gate, then verify the exact runtime, context, batch size, modalities, and concurrency.
Swipe the matrix horizontally →
| Gemma 4 model | BF16 | SFP8 | Q4_0 | Deployment boundary |
|---|---|---|---|---|
| E2B | 11.4 GB | 5.7 GB | 2.9 GB | PLE makes total storage larger than 2.3B effective parameters imply |
| E4B | 17.9 GB | 8.9 GB | 4.5 GB | 8B parameters with embeddings, 4.5B effective |
| 12B | 26.7 GB | 13.4 GB | 6.7 GB | Dense 11.95B; official BF16 files total 22.28 GiB |
| 26B A4B | 57.7 GB | 28.8 GB | 14.4 GB | All 25.2B weights reside even though 3.8B activate |
| 31B | 69.9 GB | 34.9 GB | 17.5 GB | Dense 30.7B; long context still adds state |
Source: Google AI for Developers, “Gemma 4 model overview,” retrieved August 7, 2026. Values may change with inference tool and environment.
Read the estimate
Effective is not resident.
E-model embeddings and MoE experts still consume memory even when fewer parameters drive each token.
Loading is not serving.
Context, batch size, multimodal encoders, kernels, and fragmentation can move the fit.
Eight gigabytes is a test.
The 12B Q4 artifact can be tight enough that runtime choice decides whether it loads.
12B artifact cross-check
BF16 checkpoint23,919,549,408 bytes · 22.28 GiB
QAT Q4_0 GGUF7,150,994,912 bytes · 6.66 GiB
Google loading estimates26.7 GB BF16 · 6.7 GB Q4_0
The BF16 file total plus a 20% reserve is 26.73 GiB, closely matching Google's 26.7 loading estimate. The Q4_0 GGUF artifact itself is already 6.66 GiB, so an 8 GB device should be treated as a tight experiment, not guaranteed capacity.
Primary-source inputs
The family matrix and overhead note come from Google AI for Developers. Architecture and file totals come from Google's official Hugging Face repositories.
Open the GPU memory calculator → Compare DiffusionGemma hardware → Find models for your GPU budget → Official Gemma 4 model overview → Official Gemma 4 12B model card → Official 12B BF16 checkpoint → Official 12B QAT Q4_0 files →Google lists about 26.7 GB at BF16, 13.4 GB at SFP8, and 6.7 GB at Q4_0. The official BF16 files total 22.28 GiB before runtime and context state.
The official QAT Q4_0 GGUF files total 6.66 GiB. That leaves little margin on an 8 GB card, so runtime, context length, offload behavior, and fragmentation decide whether the workload is usable.
Google lists 57.7 GB at BF16, 28.8 GB at SFP8, and 14.4 GB at Q4_0. Active parameters reduce compute, not the storage required for all expert weights.
Google lists 69.9 GB at BF16, 34.9 GB at SFP8, and 17.5 GB at Q4_0 before workload-specific validation.
The table is a model-loading estimate with approximate overhead. It does not guarantee a particular context length, modality mix, batch size, or concurrency level.
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