This tool helps you quickly estimate token counts for text across different large language models and calculate corresponding API costs. Supports GPT-4, GPT-4o, Claude 3.5, Gemini Pro, and other major models. All calculations are done locally in your browser — your text is never uploaded.
• Multi-model estimation: Simultaneously display token estimates for GPT-4, GPT-4o, Claude 3.5, Gemini Pro, and more
• Cost calculation: Automatically calculate API costs based on each model's latest pricing
• Context window: Show token usage as a percentage of context window
• Real-time estimation: Results update as you type
• Bilingual support: Automatically adjusts estimation parameters based on text language
Step 1: Enter text — Paste or type the text you want to estimate. The tool calculates token counts in real-time as you type.
Step 2: Review results — The results area shows token estimates, API costs, and context window usage for each model.
Step 3: Optimize text — Use the estimates to adjust text length, stay within context limits, and control API costs.
API Cost Budgeting: Estimate token counts and costs before calling AI APIs to avoid unexpected bills. Especially useful for batch processing scenarios.
Prompt Optimization: Optimize prompt length to reduce token consumption while maintaining effectiveness. Understanding which content uses more tokens helps streamline prompts.
Context Window Management: Ensure input text doesn't exceed model context limits, preventing information loss from truncation.
Tokenization Principles: LLMs use BPE (Byte Pair Encoding) or similar algorithms to split text into tokens. In English, a common word is typically one token, while rare words are split into multiple tokens. In Chinese, each character typically corresponds to 1-2 tokens due to the larger character set and more complex segmentation. Code and structured text (JSON, XML, etc.) generally have lower token efficiency.
Model Pricing Reference (July 2026):
| Model | Input Price | Output Price | Context Window |
|---|---|---|---|
| GPT-4o | $2.50/1M | $10/1M | 128K |
| GPT-4 Turbo | $10/1M | $30/1M | 128K |
| Claude 3.5 Sonnet | $3/1M | $15/1M | 200K |
| Gemini 1.5 Pro | $1.25/1M | $5/1M | 1M |
| GPT-4o mini | $0.15/1M | $0.60/1M | 128K |
A token is the basic unit that LLMs use to process text. One token approximately corresponds to 4 English characters or 0.75 English words. Chinese characters typically correspond to 1-2 tokens.
This tool uses character-ratio-based estimation. English error is typically within 5%, Chinese around 10%. For exact counts, use official Tokenizer tools.
Different models use different tokenizers, so the same text may have different token counts. This tool provides estimates for each model.
API cost = Input tokens x Input price + Output tokens x Output price. This tool automatically calculates estimated costs for each model.
Factors include: language type (Chinese uses more tokens), text format (code/JSON uses more), special characters and emojis, and repeated content.