How the estimate is built
Three parts add up. Weights: parameters in billions × bits per weight ÷ 8, with BF16 at 16 bits, Q8_0 at about 8.5 bits and Q4_K_M at about 4.8 bits. KV cache: the memory a model keeps for every token of the conversation so far, which NVIDIA gives as 2 × layers × key/value heads × head size × bytes per value, per token. Overhead: 1 to 2 GB for the runtime’s working buffers, counted here as 2 GB. Everything on this page is an estimate.
For the Llama 3 70B family, Meta’s paper lists 80 layers and 8 key/value heads (grouped-query attention) in a model 8,192 values wide with 64 attention heads, so each head is 128 values wide. That gives 2 × 80 × 8 × 128 × 2 bytes = 327,680 bytes, or 320 KiB, for every token.
A check against a measurement: Qwen’s published speed benchmark on an NVIDIA H20 shows Qwen3-30B-A3B using about 2,880 MB more GPU memory at a 30,720-token input than at a 1-token input. That is 96 KiB per token, reading the table’s megabytes as the usual GPU-memory mebibytes, and it is what the formula gives from the model’s configuration (2 × 48 layers × 4 key/value heads × 128 values × 2 bytes). For the dense Qwen3-32B the same table grows within 4 per cent of the formula at 30,720 tokens.