VRAMFit: LLM Calculator

Before you download gigabytes of model weights, know whether they'll actually fit.

VRAMFit tells you the largest local large language model you can run on your hardware — whether that's an NVIDIA GPU's VRAM or the unified memory on an Apple Silicon Mac. Set your memory, pick a quantization, and get a clear, instant answer.

Built for people who run models locally: llama.cpp, Ollama, LM Studio, and anyone deciding what GPU to buy next.

MEASURED, NOT GUESSED
Most calculators multiply a parameter count by a rule of thumb. VRAMFit ships the real size of the published file for every model at every quantization it is actually released in, and names the exact build each figure came from — so you can check it against the download before you start it.

That matters most where rules of thumb break. A ternary model has no 4-bit build to estimate. A natively 4-bit model barely changes size as you move up the scale. VRAMFit says what those models actually weigh, or tells you plainly that the build you picked does not exist.

WHAT IT DOES
• Enter your VRAM (or Apple Silicon RAM) and instantly see what fits
• Sorts the catalog into what runs, what runs one setting down, and what won't
• Accounts for quantization — from full precision down to 4-bit and FP4
• Factors in context length and KV cache, the memory costs people usually forget
• Switches between discrete GPU and Apple Silicon unified-memory math

FREE
• The full calculator, with quantization, context, and FP4
• A starter set of models spanning what fits and what nearly fits
• GPU and Apple Silicon modes

VRAMFit Pro (one-time upgrade)
• The complete catalog of 73 current open models, measured
• Per-quantization memory breakdown for every model
• Advanced tools: KV-cache compression and multi-token prediction estimates

PRIVATE BY DESIGN
VRAMFit runs entirely on your device. No account, no sign-in, no tracking, and nothing about you leaves your iPhone. The numbers you enter stay with you.

Stop guessing whether a model will fit. Check first, download once.