Token Counter

What is a Token Counter?

A token counter is a tool that counts the number of tokens in a given piece of text based on a specific language model's tokenizer. Tokens are the fundamental units that LLMs (like GPT, o1, and Claude) use to process text – they can be whole words, parts of words, or punctuation. Counting tokens accurately is essential for estimating API usage, managing costs, and optimising prompts for performance.

Our token counter supports a wide range of models and uses the official `gpt-tokenizer` library to give exact counts. You can also visualise token boundaries and view token IDs – making it a valuable tool for developers, researchers, and content creators.

How to Use the Token Counter

Counting tokens with our tool is quick and straightforward. Follow these steps:

• Enter your text: Paste your content into the input area, upload a text file, or load text from a URL.
• Select a model: Choose the LLM you plan to use (e.g., GPT‑5, o1, GPT‑4) – the tool automatically uses the correct tokenizer.
• Count tokens: Click "Count Tokens" or enable "Auto Update" to see the token count instantly.
• View output: Switch between a colored token view, token IDs, or hide the output – all displayed in real time.
• Copy or download: Copy the tokenised output or download it as a text file for further analysis.

Why Count Tokens?

Token counting is a key activity for anyone working with large language models. Here's why it matters:

• Estimate API costs: Most LLM APIs charge per token – knowing your token count helps you budget accurately.
• Optimise prompts: Stay within model context windows by trimming or compressing text to reduce token usage.
• Debug and analyse: See exactly how your text is tokenised, which can help when fine‑tuning or troubleshooting prompts.
• Improve efficiency: Reduce token count without losing meaning, speeding up inference and lowering latency.
• Plan for multi‑turn conversations: Keep track of total tokens in chat history to avoid exceeding limits.

Key Features of the Token Counter

Our token counter is built for accuracy and ease of use. Here are its standout features:

• Multi‑model support: Supports over 70 models including GPT‑5, GPT‑4, o1, o3, o4, codex‑mini, and more – with automatic tokenizer selection.
• Exact token counting: Uses the official `gpt-tokenizer` library for accurate results that match each model's behavior.
• Visual tokenisation: Colored view shows each token as a separate block, making it easy to understand how text is split.
• Token IDs display: Switch to view the numeric token IDs, useful for debugging and understanding vocabulary.
• Multiple input methods: Paste text, upload files, or fetch content via URL – flexible for any workflow.
• Auto‑update & copy/download: Live counting with optional auto‑update, and one‑click copy or download of results.
• Free and private: No registration, no server uploads – everything runs in your browser.

Who Needs a Token Counter?

A token counter is essential for a variety of roles:

• Developers: Estimate token usage for API calls, plan context windows, and debug prompt engineering.
• Data scientists & researchers: Analyse tokenisation patterns and prepare datasets for fine‑tuning.
• Content creators: Optimise blog posts, articles, and long‑form content to fit model constraints without sacrificing quality.
• Product managers: Forecast costs and usage for AI‑powered products that rely on LLM APIs.
• Educators and students: Learn how tokenisation works and experiment with different models.

Related Free Online Tools

Explore these other free tools to enhance your text and document workflow:

• Word Counter Online: count words, characters, and sentences.
• Free Character Counter: count characters with and without spaces.
• Free JSON Formatter and Prettifier: format and validate JSON data.
• Markdown to PDF – convert Markdown to professional PDFs.
• Signature Generator – create digital signatures for documents.

Your data stays private – all processing is done client‑side. No text is uploaded to any server. Your content remains yours.

Frequently Asked Questions

What is a token counter?

A token counter is a tool that counts the number of tokens in a piece of text based on a specific LLM's tokenizer. Tokens are the basic units that models process, and counting them helps estimate API usage and costs.

How does token counting work?

The tool uses the same tokenizers as the models (e.g., cl100k_base, o200k_base) to split text into tokens. It then displays the token count and optionally visualizes each token with colors.

Which models are supported?

We support a wide range of models including GPT‑5, GPT‑4, GPT‑3.5, o1, o3, o4, codex‑mini, and many more. The correct tokenizer is automatically selected based on the model.

Is the token counter free?

Yes, the token counter is completely free to use online with no registration or subscription required.

Can I upload a file to count tokens?

Yes, you can upload a text file (or JSON) using the upload button. You can also load text from a URL or paste content directly.

What does the colored token view show?

The colored view displays each token with a different background color, making it easy to see how the text is split. Whitespace tokens are shown normally without color.

Can I see the token IDs?

Yes, switch the output view to 'Token IDs' to see the integer IDs for each token, which correspond to the model's vocabulary.

How accurate is the token count?

The count is exact for the selected model because we use the same tokenizer implementation as the model. The result is based on the official gpt-tokenizer library.