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Live result

5.59 GB estimated

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Context Window Memory Calculator puts this setup around 5.59 GB including rough runtime overhead.

Weights

-4.50 GB
Q4_K_M

KV cache

-0.29 GB
8K context
How It Works

3 inputs. Instant results.

01

Set the scenario

Choose realistic hardware, model, and context assumptions.

02

Read the result

The hero shows a working result instead of a decorative promo block.

03

Act on the outcome

Use the result to adjust fit, speed, quantization, or context.

Features

Everything that powers context window memory calculator.

01

Planning-first

Built to make local-AI decisions easier to reason about.

02

Local-AI focused

Built to make local-AI decisions easier to reason about.

03

Interactive hero

Built to make local-AI decisions easier to reason about.

04

Runyard design system

Built to make local-AI decisions easier to reason about.

05

Target model size

Grounded in the actual inputs and outputs this page is designed around.

06

KV cache growth curve

Grounded in the actual inputs and outputs this page is designed around.

07

Built for long chat and RAG use cases

Grounded in the actual inputs and outputs this page is designed around.

08

Standalone tool

Grounded in the actual inputs and outputs this page is designed around.

Spotlight

The differentiator behind context window memory calculator.

KV at 8K context

Unknown cost~0.3 GB7B Q4 baseline

KV at 32K context

0.3 GB~1.2 GB4× growth

KV at 128K context

Guessing~4.8 GBPlan this ahead

Visual comparison

Clarity
Fit
Actionability
Reading Results

How to read the output tiers.

Comfortable

<70%

Enough breathing room for normal use.

Tight

70%-95%

Should work, but overhead matters.

Borderline

95%-110%

Likely needs one tradeoff.

Too heavy

>110%

Time to step down.

Quick Reference

Common setups at useful defaults.

ScenarioBaselineResultNotes
Starter setup7B / Q4 / 8KLight local targetGood first benchmark
Balanced setup8B / Q4 / 16KEveryday sweet spotWorks for many users
Heavier setup14B / Q5 / 16KQuality-focused targetNeeds stronger hardware
Stretch setup32B / Q4 / 16KAmbitious local targetUseful upper bound

* These are approximations for planning, not a promise of exact runtime behavior.

Benefits

Why people use context window memory calculator.

01

Faster decisions

It helps eliminate dead-end local AI choices before you download, benchmark, or configure too much.

02

Clearer tradeoffs

The page turns a raw estimate into something you can actually act on.

03

Useful on its own

The hero provides a working tool surface while the rest of the page explains what the output means.

FAQ

Questions people ask before using context window memory calculator.

How does context window size affect memory?
KV cache grows linearly with context length. At 8K it adds a few hundred MB. At 64K–128K it often exceeds model weight cost — a 7B model at Q4 needs ~0.3 GB KV at 8K but ~4.8 GB at 128K.
What is KV cache and why does it matter?
KV (key-value) cache stores attention patterns for each token in the active context. It accumulates as conversation grows and is the main reason long-context inference costs more VRAM than a simple model load.
When does context become the real bottleneck?
Typically past 16K tokens. At that point, KV cache starts competing with model weights for available VRAM. At 128K, the cache alone can exceed model weights for most consumer GPUs.
Does this apply to Ollama's num_ctx setting?
Yes. Ollama's num_ctx maps directly to the context window. Setting num_ctx=32768 uses significantly more memory than the default 2048 — sometimes enough to cause silent failures on limited hardware.
How much more memory does 128K context need vs 8K?
Roughly 16× more KV cache. A 7B model at Q4 uses ~0.3 GB KV at 8K and ~4.8 GB at 128K. On a 12 GB GPU, that difference can push a setup over the edge.
Should I always maximise context length?
No. Set it to what the task actually needs. Chat sessions rarely exceed 8K–16K. Long RAG or code review sessions may justify 32K. 128K is expensive and rarely fully utilised locally.

RUNYARD.DEV / Tools / Context Window Memory Calculator

Estimates on this page are directional and should be validated against your actual runtime and hardware.

Copyright 2026 Runyard.devPlanning estimates only. Real-world runtime behavior may vary by backend and hardware.