LLM Context Window Budget Visualizer
Visualize context window usage: System Prompt, User Prompt, Retrieved RAG chunks, Conversation History, and Output capacity.
Concept Breakdown: How Tokenizers Chunk Text & Encode IDs
Computers do not read words like humans. They only understand numbers. An AI chops your sentence into Lego-like building blocks called "tokens". Common words (like "process" or "all") are 1 block, while rarer or longer words get split into smaller puzzle pieces (like "Transf" + "ormers").
Every single space (␣), hyphen (-), and period (.) counts as its own separate token. When you add up the word pieces plus the spaces and punctuation, 8 written words become 23 tokens (a 2.88 ratio).
AI companies (like OpenAI or Anthropic) bill you per token, not per word or letter! For example, GPT-4o charges $5.00 for every 1 Million tokens. This tool calculates the exact fraction of a cent your text would cost.
Estimated API Execution Cost
| Model | Input Price / 1M Tokens | Cost for This Input |
|---|---|---|
| GPT-4o (OpenAI) | $5.00 | $0.000305 |
| Claude 3.5 Sonnet (Anthropic) | $3.00 | $0.000183 |
| GPT-4o mini (OpenAI) | $0.15 | $0.000009 |
Practice Challenge: Estimate the Tokens
Without looking at the counter, enter a paragraph into the box above and guess how many tokens it produces.
Quick Reference & Instructions
Simple steps, pro tips, and execution details
Provide Inputs
Type, paste, or select your values in the form fields below.
Instant Live Analysis
Calculations and formatting happen automatically with zero delay as you type.
Copy or Use Output
Copy results or apply the clean output directly to your projects.
How It Works
Provides interactive slider budgets for models with 8k, 32k, 128k, and 1M context limits, warning when prompt overflow occurs.
Frequently Asked Questions
Common questions about calculations, assumptions, and edge cases.
Yes, LLM Context Window Budget Visualizer is 100% free with unlimited calculations and zero paywalls or subscriptions.
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