Context Window Planner
Free online context window planner, no installation required. Visualize prompt usage in LLM context window
About the Context Window Planner
The Context Window Planner helps you optimize prompts for large language models by visualizing token usage. It ensures your prompts fit within a model's context limits while maximizing the space available for the model's response.
Understanding the Context Window
Every LLM has a maximum context window (for example, 128K for GPT-4, 200K for Claude). This includes your system prompt, conversation history, and a buffer for the expected output. Planning helps you avoid truncated responses or wasted tokens.
How to Use
Select your target model. Enter the system prompt, conversation history, and expected output length. The visualization chart shows how the context space is being used. Adjust your content to fit within the limit while reserving room for the response.
Token Estimation
Click Auto Estimate to automatically compute the token count of your content. The tool uses accurate per-model tokenization. Check the usage information to see the exact token count and remaining capacity.
▶What happens if I exceed the context limit?
▶How accurate is the token estimation?
▶Should I always use the maximum context window?
▶What is the difference between input and output tokens?
▶Can I save my context plan?
▶Which models are supported?
If this tool has been helpful to you, consider buying me a coffee.
Buy me a coffee