LLM Quantization Calculator: Compare Every Level at Once

By Cedrick Reese, Ready Utilities

Last updated: September 2026

This LLM quantization calculator shows every format at once instead of picking one for you: enter a model size and see the file size and quality tradeoff across all seven levels side by side. For a fit check against your specific hardware, use the hardware calculator instead. That tool answers a different question, and the two are meant to be used together, not interchangeably.

Compare quantization levels

Format	Size	Quality	Fits?

How this differs from the hardware calculator

The hardware calculator is model-specific: pick a real model (or a custom parameter count) and get one exact number for one quantization level, using that model's real architecture for the context-memory math. This calculator is quantization-first: it shows how the same parameter count scales across every format at once, which is more useful when you're still deciding which level to download rather than checking a final answer. Small differences between the two tools' numbers for the same model, typically within about 10%, come from per-model architecture variation (layer count, attention head count, vocabulary size) that this simpler tool doesn't account for. For a final, precise number, cross-check with the hardware calculator on your specific model.

How the sizes are calculated

Sizes use the same formula and bytes-per-weight figures already published on quantization explained: parameter count multiplied by bytes-per-weight for each format. Quality tiers use that same page's wording, not a separate rating scale invented for this tool. See that page for the full reasoning behind each tier and a worked decision framework for picking a level.

Bytes-per-weight figures and quality tiers are reused directly from this site's own quantization explained page, not re-derived, so the two pages never disagree with each other. The fit-verdict thresholds (comfortable/tight/won't fit) are the same ones the hardware calculator uses, for the same reason. This page gets rechecked whenever those source figures change.

Sources

Frequently asked questions

Why does this show a different number than the hardware calculator for the same model?

They're built for different questions. This calculator estimates from parameter count alone, the same way across any model. The hardware calculator uses each specific model's real architecture, so it's more precise. Differences of around 10% between the two are normal and expected, not a bug in either one.

Which quantization level should I actually pick?

See the decision framework on the quantization explained page rather than a rule of thumb here. It covers the VRAM-budget approach in full and explains why Q5_K_M or Q4_K_M is the right default for most people.

Does a higher quality tier always mean a meaningfully better model?

No. The jump from Q4_K_M to Q5_K_M or Q6_K is real but small; the jump from Q3_K_M down to Q2_K is where quality loss becomes easy to notice. Most of the practical benefit sits between Q4_K_M and Q6_K, not above it.