---
title: "Introducing 100K context windows"
description: "Claude’s context window has expanded from 9K to 100K tokens, or about 75,000 words, enabling businesses to submit hundreds of pages and sustain conversations for hours or days. The announcement describes using the larger window to digest documents, synthesize information across multiple files, answer questions, and work with full codebases, with the claim that complex questions may perform substantially better than vector-search approaches. In a test, Claude-Instant processed the 72K-token text of The Great Gatsby after one line was altered, identified the change correctly, and responded in 22 seconds; 100K tokens is also described as roughly six hours of audio. The capability is available through the API, with examples including financial analysis, legal review, developer-documentation search, podcast summarization, and rapid prototyping."
---

# Introducing 100K context windows

[Anthropic](https://yomu.fyi/company/anthropic) · Aug 26, 2026

**Type:** Announcement

## Summary

Claude’s context window has expanded from 9K to 100K tokens, or about 75,000 words, enabling businesses to submit hundreds of pages and sustain conversations for hours or days. The announcement describes using the larger window to digest documents, synthesize information across multiple files, answer questions, and work with full codebases, with the claim that complex questions may perform substantially better than vector-search approaches. In a test, Claude-Instant processed the 72K-token text of The Great Gatsby after one line was altered, identified the change correctly, and responded in 22 seconds; 100K tokens is also described as roughly six hours of audio. The capability is available through the API, with examples including financial analysis, legal review, developer-documentation search, podcast summarization, and rapid prototyping.

## Context

The previous Claude context window was 9K tokens. The expansion is intended to let businesses submit hundreds of pages of material, sustain conversations for hours or days, and ask questions requiring synthesis across multiple documents.

## Approach / What changed

The context window was expanded to 100K tokens, and the announcement demonstrates using Claude to process long documents, compare text, answer cross-document questions, summarize audio transcripts, analyze business and legal materials, search developer documentation, and work with entire codebases. The capability is available through the API.

## Takeaways

- Claude’s 100K-token context window corresponds to around 75,000 words and is described as roughly six hours of audio.
- Claude-Instant identified a modified line in the 72K-token text of The Great Gatsby in 22 seconds.
- The API supports long-context uses including document synthesis, legal analysis, podcast summarization, developer-documentation questions, and codebase prototyping.

**Tags:** [API](https://yomu.fyi/topic/api), [Claude](https://yomu.fyi/topic/claude), [LLMs](https://yomu.fyi/topic/llm)

- Source: [Anthropic](https://www.anthropic.com/news/100k-context-windows)
- Source URL: https://www.anthropic.com/news/100k-context-windows
- Ingested by Yomu: 2026-09-09T11:36:19.569Z

[Read original post](https://www.anthropic.com/news/100k-context-windows)