---
type: "GlossaryTerm"
title: "1 Million Token Context Window"
description: "A 1 Million Token Context Window is the maximum number of tokens a large language model can read and process in a single session — 1,000,000 tokens correspond t"
resource: "https://www.contextstudios.ai/glossary/1-million-token-context-window"
language: "en"
tags: ["infrastructure"]
generated:
  by: "process:contextstudios-md/1"
  at: "2026-10-08T20:46:20.659Z"
status: "stable"
---

# 1 Million Token Context Window

A 1 Million Token Context Window is the maximum number of tokens a large language model can read and process in a single session — 1,000,000 tokens correspond to roughly 750,000 English words. The context window determines how much information an LLM reads and processes at once: the prompt, tool results, and already generated text share this capacity. A larger window means more history per run, but also higher compute costs per request, because the attention mechanism must iterate over all positions. Concretely, Claude Fable 5 (Anthropic, June 2026) uses a 1 million token context window and can analyze an entire software repository with over 200 files in a single call — a clear jump over its predecessor Claude Fable 3 with only 200,000 tokens. Unlike the general term Context Window, which takes different values depending on the model (e.g. 8,192, 128,000, or 1,000,000), the figure 1 million represents the largest window currently available among common frontier models.