Context Window Visualizer
Visualize how much of an AI model's context window your text fills. Supports GPT-5.4, Claude, Gemini, and more. Paste text or enter a token count.
Context window: 1,000,000 tokens
Tokens Used
0
Context Window
1,000,000
Percentage Used
0.0%
Remaining
1,000,000
≈ 751,879.699 words
Frequently Asked Questions
What is a context window in AI?
A context window is the maximum amount of text — measured in tokens — that an AI model can process in a single request. It includes everything the model "sees" at once: your system prompt, conversation history, and the current message. Models like GPT-5.4 support up to 1,000,000 tokens, while others cap at 128,000 or less. Staying within the context window is critical for reliable, coherent responses.
What happens when you exceed the context window?
When your input exceeds the model's context window, the API will return an error and refuse to process the request. Some applications silently truncate the oldest messages to fit within the limit — which can cause the model to "forget" important context from earlier in the conversation. Always monitor your token usage to avoid unexpected truncation or errors.
Which AI model has the largest context window?
As of early 2026, Google's Gemini 3.1 Pro and xAI's Grok 4.20 lead with 2,000,000-token context windows. GPT-5.4 and Claude Opus 4.6 support 1,000,000 tokens. Larger context windows allow you to feed in entire codebases, long documents, or extended conversation history — but larger inputs also increase inference cost and latency.