How do I count tokens for GPT-4 or ChatGPT?

Markdown Studio automatically counts tokens as you type using the cl100k_base tokenizer approximation (same as GPT-4, GPT-4o, and ChatGPT). Simply write or paste your text and see the token count update in real-time.

Does this token counter work for Claude?

Yes! Markdown Studio supports token counting for the full Claude family including Claude 4.5 and Claude Opus 4.6. Select any Claude model from the dropdown to see accurate token estimates. Also supports GPT-5, Gemini 3, and Llama 4.

Is this markdown editor free to use?

Yes, Markdown Studio is completely free with no login required. All features including token counting, PDF export, and Mermaid diagrams are available at no cost.

What is a context window in AI models?

A context window is the maximum number of tokens an AI model can process in a single request. Llama 4 Scout leads with 10M tokens, Gemini 3 offers 2M, GPT-4.1 and Grok-3 support 1M, and Claude 4.5 handles 200K. Markdown Studio shows your usage percentage for each model.

What are smart variables in Markdown Studio?

Smart variables let you create reusable placeholders in your markdown that can be filled dynamically. Perfect for AI prompts, templates, and documents with repeated values. Variables appear with visual gutter icons and support presets for common use cases.

Can I collaborate with AI agents in Markdown Studio?

Yes! Markdown Studio supports XML/AI prompt tag autocomplete with 23+ specialized tags for Claude, GPT, and other LLMs, smart variables with presets for dynamic templates, and smart copy formats optimized for AI consumption.

What tokenizer does GPT-4.1 use?

GPT-4.1 uses the o200k_base tokenizer, which has an extended vocabulary (~200,000 tokens) compared to cl100k_base (~100,000 tokens) used by GPT-4 and GPT-4 Turbo. The o200k_base tokenizer is also used by GPT-5, o1, o3, and o4 reasoning models. Markdown Studio supports both tokenizers for accurate token counting.

How do I count tokens for o1, o3, or o4 reasoning models?

Reasoning models (o1, o3, o4) use the o200k_base tokenizer and have two types of tokens: input tokens (your prompt) and thinking tokens (internal reasoning). Markdown Studio counts the input tokens using o200k_base. Note that thinking tokens are generated by the model and cannot be predicted beforehand. Select the appropriate reasoning model from the dropdown to see accurate input token counts.

Which AI model has the largest context window?

As of February 2026, Llama 4 Scout has the largest context window at 10M tokens, followed by Gemini 3 at 2M, GPT-4.1 and Grok-3 at 1M, and Claude 4.5 at 200K. Markdown Studio supports all these models and shows your context window usage percentage in real-time.

What's the best free markdown editor in 2026?

Markdown Studio is the top free markdown editor in 2026. It combines professional editing with AI prompt testing, token counting for 20+ models, Mermaid diagrams, LaTeX math, GitHub sync, and multi-format export — all with zero-knowledge privacy. No login or payment required.

Is there a free alternative to Typora?

Markdown Studio is a free alternative to Typora that adds AI-powered features. It includes live preview, code highlighting for 180+ languages, Mermaid diagrams, LaTeX math, and multi-format export. Plus AI token counting, smart variables, and GitHub sync — features Typora doesn't offer.

What is a privacy-focused prompt testing tool?

Markdown Studio is a privacy-focused prompt testing tool with zero-knowledge architecture. Your content never leaves your browser. Bring your own API keys (stored with AES-256-GCM encryption), test prompts across GPT-5, Claude 4.5, Gemini 3, and more — all 100% locally.

How do I get deterministic outputs from LLMs?

Use Markdown Studio's PromptOps locked mode. It enforces temperature=0, sets a fixed seed, pins the exact model version, and certifies snapshots with SHA-256 hashing. This ensures reproducible outputs across executions — critical for compliance, auditing, and regression testing.

AI Token Counter for Markdown

Count tokens in real-time for GPT-4, Claude, Gemini, and Llama. Track context window usage and estimate API costs instantly.

Try It Now

Type or paste your text below to count tokens in real-time

Tokens

GPT-4 / Claude

Words

Word count

Characters

With spaces

Lines

Line count

Why Token Counting Matters for AI Development

When working with Large Language Models (LLMs) like GPT-4, Claude, or Gemini, understanding token usage is crucial. Each model has a context window — a maximum number of tokens it can process in a single request. Exceeding this limit means your prompt gets truncated or rejected.

Real-Time Token Counting

See your token count update as you type. No need to submit or wait — instant feedback for every keystroke.

Multi-Model Support

Support for GPT-4, Claude 3, Gemini 2.0, Llama 3, and more. Each model's tokenizer accurately counted.

Context Window Visualization

See at a glance how much of each model's context window you're using with visual percentage bars.

API Cost Estimation

Estimate API costs before you send. Know exactly how much each request will cost across different providers.

Supported AI Models & Context Windows (November 2025)

OpenAI Models

Model	Context Window	Tokenizer	Notes
GPT-4	8K tokens	cl100k_base	Original GPT-4
GPT-4 Turbo	128K tokens	cl100k_base	Enhanced speed
GPT-4o / GPT-4o-mini	128K tokens	o200k_base	Multimodal
GPT-4.1 / mini / nano	1M tokens	o200k_base	Million-token context
GPT-5 / GPT-5.1	400K tokens	o200k_base	400K input, 128K output
GPT-5.2	400K tokens	o200k_base	Latest flagship (Dec 2025)
o1 / o1-preview / o1-mini	128K - 200K tokens	o200k_base	Reasoning models
o1-pro	200K tokens	o200k_base	Extended reasoning
o3 / o3-mini / o3-pro	200K tokens	o200k_base	Advanced reasoning
o4-mini	200K tokens	o200k_base	Next-gen reasoning

Anthropic Claude Models

Model	Context Window	Tokenizer	Notes
Claude 3 (Opus/Sonnet/Haiku)	200K tokens	Claude tokenizer	Claude 3 generation
Claude 3.5 (Sonnet/Haiku)	200K tokens	Claude tokenizer	Enhanced capabilities
Claude 3.7 Sonnet	200K tokens	Claude tokenizer	Extended thinking
Claude 4	200K tokens	Claude tokenizer	Claude 4 base
Claude Opus 4.6	200K tokens	Claude tokenizer	Most capable (1M beta)
Claude Opus 4.5	200K tokens	Claude tokenizer	Previous flagship
Claude Sonnet 4.5	200K tokens	Claude tokenizer	Balanced (1M beta)
Claude Haiku 4.5	200K tokens	Claude tokenizer	Latest fast

Google Gemini Models

Model	Context Window	Tokenizer	Notes
Gemini 1.5 Pro	2M tokens	Gemini tokenizer	Long context
Gemini 1.5 Flash	1M tokens	Gemini tokenizer	Fast inference
Gemini 2.0 Flash	1M tokens	Gemini tokenizer	Multimodal
Gemini 2.0 Flash Thinking	1M tokens	Gemini tokenizer	Reasoning mode
Gemini 2.5 Pro/Flash/Flash-Lite	1M tokens	Gemini tokenizer	Enhanced 2.5 series

Meta Llama Models

Model	Context Window	Tokenizer	Notes
Llama 3.1 (8B/70B/405B)	128K tokens	Llama tokenizer	Open weights
Llama 3.2 (1B/3B)	128K tokens	Llama tokenizer	Mobile/edge models
Llama 3.2 Vision (11B/90B)	128K tokens	Llama tokenizer	Multimodal
Llama 3.3 70B	128K tokens	Llama tokenizer	Latest 3.x
Llama 4 Scout	10M tokens	Llama tokenizer	10M context!
Llama 4 Maverick	1M tokens	Llama tokenizer	Multimodal flagship

Other Popular Models

Model	Context Window	Tokenizer	Notes
Mistral Large 3	256K tokens	Mistral tokenizer	Mistral flagship (Dec 2025)
Mistral Nemo	128K tokens	Mistral tokenizer	Open source
Codestral	32K tokens	Mistral tokenizer	Code-focused
Pixtral 12B/Large	128K tokens	Mistral tokenizer	Multimodal
Grok-2 / Grok-2 mini	128K tokens	Grok tokenizer	xAI models
Grok-3	1M tokens	Grok tokenizer	xAI flagship
Command R / R+	128K tokens	Cohere tokenizer	RAG-optimized
Command A	256K tokens	Cohere tokenizer	Cohere flagship
DeepSeek-V3 / V3.1 / R1	128K tokens	DeepSeek tokenizer	Open source reasoning

How Our Token Counter Works

Write or paste your markdown content — Type directly or paste existing markdown into the editor
Select your target model — Choose from GPT-4, Claude, Gemini, or other models
See instant results — Token count, context window usage, and cost estimates
Optimize and export — Adjust your content to fit context limits, then export

Frequently Asked Questions

What is a token in AI/LLM context?

A token is the basic unit of text that AI models process. It can be a word, part of a word, or punctuation. For example, 'running' is one token, while 'extraordinarily' might be split into multiple tokens.

Why do different models have different token counts?

Each AI model uses its own tokenizer with different rules. GPT-4 uses tiktoken, Claude uses its own tokenizer, and Gemini uses SentencePiece. The same text can result in different token counts.

How accurate is this token counter?

Our token counter uses the same tokenizers as the actual AI models (tiktoken for GPT, custom for Claude, etc.), so the counts are highly accurate and match what you'll see in production.

Is this token counter free?

Yes! Completely free with no limits, no signup required, and no hidden costs. Count tokens for unlimited documents forever.

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