One formula that tells you exactly what fits on your GPU
If you’re running models locally, thinking “model → VRAM” falls apart once you account for how the weights were trained and quantized in the first place.
There’s a better way to think about it:
VRAM (in GB) ≈ Parameters (in billions) x (effective bits per weight ÷ 8)
That’s it.
This one formula explains everything across:
FP16 / BF16
FP8 / INT8
GPTQ / AWQ / NF4
