Free planning tool // model → precision → memory

LLM VRAM calculator

Choose a model and weight precision, add operating headroom, and compare the indexed single-device options that clear the resulting memory target. Results are planning estimates—not runtime support or live-price guarantees.

VRAM fit calculation
single-device planning estimate
Weight precision
44GBDataset baseline
51GBPlanning target
Single-device memory mapgreen capacities fit

Smallest memory footprint. Headroom is a user-controlled planning buffer; actual use varies by runtime, context length, KV cache, concurrency, and offloading.

Source: Official Qwen GGUF model card

How the VRAM estimate works

The calculator begins with GPU Hunter's model-specific memory baseline for Q4, Q8, or FP16 weights. The optional headroom setting increases that baseline before comparing it with the memory capacity of every device in the current index.

This is intentionally a capacity screen, not a promise that a model will run in every configuration. Context length, KV cache, batching, concurrency, runtime allocations, drivers, and offload strategy all affect real memory use. Validate the final setup in the runtime you plan to use.

Why quantization changes the answer

Lower-bit quantization compresses model weights. That can make a model viable on less expensive hardware, but formats differ in quality, kernel support, and speed. Treat Q4, Q8, and FP16 as distinct deployment choices rather than interchangeable labels.

LLM VRAM requirements by model

These values are GPU Hunter's weight-size baselines before optional operating headroom. They are not measurements of every possible context length or runtime.

ModelQ4Q8FP16Listed contextSource
Qwen3 32B19GB36GB64GB128KModel card ↗
Qwen2.5 72B44GB77.5GB145GB128KModel card ↗
Qwen3 235B-A22B132GB240GB470GB128KModel card ↗
Llama 3.3 70B40GB75GB140GB128KModel card ↗
DeepSeek V3380GB700GB1300GB128KModel card ↗
Llama 3.1 8B5GB9GB16GB128KModel card ↗
Qwen3 14B8GB15GB28GB128KModel card ↗
Mistral 7B4GB8GB14GB32KModel card ↗
Gemma 2 27B16GB30GB54GB8KModel card ↗
Codestral 22B13GB24GB44GB32KModel card ↗

Frequently asked questions

How much VRAM do I need for an LLM?

It depends on the model size, weight precision, context length, runtime overhead, KV cache, and concurrency. Select a known model and quantization to get a planning baseline, then add headroom for the way you intend to run it.

What is the difference between Q4, Q8, and FP16?

Q4 stores weights at roughly four-bit precision and generally uses the least memory. Q8 uses more memory in exchange for higher weight precision. FP16 is a full-weight 16-bit baseline and usually requires substantially more memory. Exact quality and performance depend on the quantization method and runtime.

How much operating headroom should I add?

Fifteen percent is GPU Hunter's default planning allowance, not a universal requirement. Longer context, larger KV caches, batching, concurrent users, and runtime behavior may require more. CPU or multi-GPU offloading changes the calculation.

Does enough VRAM mean the model is compatible?

No. Enough memory only clears the capacity constraint. Confirm that your runtime, drivers, model format, kernels, operating system, and device architecture are supported.

Are the GPU prices in the results live?

No. They are dated reference values from the GPU Hunter dataset, last updated Apr 30, 2026. Always verify the current price, condition, seller, and availability.