LLM Token Counter & Visual Tokenizer

Live BPE tokenization, color-coded token chips, context window utilization, and 2026 API cost estimation for GPT-4o, Claude, Gemini & DeepSeek.

0Tokens (o200k_base)
0Characters
0Words
0Chars / Token
0sReading Time
$0.00Est. Input Cost (GPT-4o)
Context Window Gauge0 / 128,000 tokens (0.00%)

Your Prompt, Document, or Code

Encoding: o200k_base
Drop files (.txt, .md, .py, .js, .json, .csv) to inspect tokens

Visual Token Stream (Colored Chips)

Each distinct box represents an individual token produced by the BPE tokenizer. Hover over any chip to inspect token details.

Hover or tap any token chip below to inspect its token ID, string length, and byte encoding.
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No text entered yet. Enter or paste a prompt in the input tab to inspect live colored token segments.

Tokenizer Comparison Across Model Families

Observe how the identical prompt consumes different token totals across distinct tokenizer vocabularies.

Model FamilyTokenizer EncodingVocabulary SizeToken CountChars / TokenEfficiency vs cl100kContext Limit

API Cost Simulator & Cloud Budgeting

Project exact costs for high-throughput inference, batch jobs, and enterprise API workloads across 2026 pricing tiers.

Calls executed per 24-hour cycle
Estimated completion length generated by model
Standard official API rate card pricing

2026 Frontier Model Cost Breakdown

ModelProviderInput TokensOutput TokensInput $/1MOutput $/1MCost / CallCost / 1k CallsMonthly (30 Days)

Official rates updated for 2026. Includes OpenAI o1, o3-mini, GPT-4o, Anthropic Claude 3.7 & 3.5 Sonnet, Google Gemini 2.0 Flash, DeepSeek V3/R1, and Meta Llama 3.3. Volume discounts and commitment tiers may further reduce production expenses.

Comprehensive Guide: LLM Tokenization, BPE Mechanics & Cost Optimization

1. What is a Token and How Does Byte Pair Encoding (BPE) Work?

Large Language Models (LLMs) do not process raw text strings or complete sentences directly. Instead, text is transformed into numerical vectors through a process called tokenization. Most state-of-the-art models—including OpenAI's GPT-4o, Anthropic's Claude 3.7, Google's Gemini, and DeepSeek—employ variants of Byte Pair Encoding (BPE).

During BPE tokenization, a model relies on a predefined vocabulary of tokens. Common short English words (such as " the", " with", " database") constitute a single token. However, rare words, domain-specific terminology, code variable names (like getUserProfileByAccountId), and non-Latin characters are segmented into smaller subword chunks or individual UTF-8 bytes.

OpenAI o200k_base (GPT-4o, o1, o3)

  • Vocabulary Size: 200,000 tokens
  • Avg Characters / Token: 4.4 – 4.8 chars
  • Non-English Efficiency: Up to 35% fewer tokens than GPT-4
  • Code Performance: Compresses indentation and syntax efficiently

OpenAI cl100k_base (GPT-4, GPT-3.5)

  • Vocabulary Size: 100,277 tokens
  • Avg Characters / Token: 3.8 – 4.1 chars
  • Non-English Efficiency: High token overhead on Asian and Indic scripts
  • Standard: Foundational benchmark for embeddings (ada-002)

Anthropic Claude Custom BPE

  • Vocabulary Size: ~65,000 tokens
  • Avg Characters / Token: 3.9 – 4.2 chars
  • Context Window: 200,000 tokens (up to ~150,000 words)
  • Prompt Caching: Fast checkpointing for system prompts

Google Gemini SentencePiece

  • Vocabulary Size: 256,000 tokens
  • Avg Characters / Token: 4.3 – 4.6 chars
  • Context Window: 1M – 2M tokens
  • Multimodal: Unifies audio, video frames, and text tokens

2. The "Token Tax" on Non-English Languages and Code

A frequent issue for international engineering teams is the language disparity in LLM billing. In English, a standard sentence like "Artificial intelligence transforms modern software development." consumes approximately 7 tokens. However, in scripts with complex alphabetic or syllabic structures (such as Hindi, Arabic, Japanese, or Cyrillic), older tokenizers like cl100k_base had to fragment words into multiple byte pieces, consuming 2x to 4x more tokens for the identical semantic meaning.

The introduction of o200k_base in 2024–2026 dramatically lowered this penalty by dedicating dedicated vocabulary entries to high-frequency international terms and non-Latin character compounds.

3. Five Proven Strategies to Reduce LLM API Token Costs

  1. Implement System Prompt Caching: Providers like OpenAI and Anthropic offer 50% to 80% pricing discounts for cached prompt prefixes. Structuring your API calls so that large system prompts and schema definitions remain unchanged at the beginning of the prompt allows you to reuse cached KV states across requests.
  2. Strip Redundant Markdown & JSON Padding: When passing data tables or records to an LLM, converting verbose JSON structures (repeated key names across thousands of records) into compact TSV or CSV format typically saves between 30% and 55% of input tokens.
  3. Prune Few-Shot Examples Dynamically: Rather than hardcoding 10 static few-shot demonstrations into every call, use a local similarity search (BM25 or lightweight embeddings) to inject only the single most relevant example.
  4. Enforce Constrained Output Max Tokens: If an extraction task only requires a single boolean or enum value, set max_tokens: 16 to prevent runaway generation loops and hallucinatory disclaimers.
  5. Utilize Prompt Token Minimization: Use our companion Prompt Token Minimizer to deterministically eliminate filler words, polite fluff, and verbose conversational phrasing prior to making API calls.

Frequently asked questions

How does this token counter split and count tokens?

This tool implements a byte-level Byte Pair Encoding (BPE) segmentation algorithm aligned with OpenAI's o200k_base and cl100k_base tokenizers, as well as benchmarked scaling models for Anthropic Claude (Claude 3.7/3.5), Google Gemini 2.0/1.5, DeepSeek V3/R1, and Meta Llama 3.3. It isolates whitespace prefixes, alphanumeric word stems, subword fragments, contraction suffixes, and multi-byte Unicode runes.

What is the difference between o200k_base and cl100k_base?

cl100k_base is the 100,000-token vocabulary used by GPT-4 and GPT-3.5-turbo. o200k_base is OpenAI's expanded 200,000-token vocabulary introduced with GPT-4o, o1, and o3-mini. The larger vocabulary is significantly more efficient for non-English languages (consuming 20% to 40% fewer tokens for Spanish, Chinese, Hindi, Arabic) and structured code indentation.

Why do token counts differ between GPT-4o, Claude, Gemini, and DeepSeek?

Each LLM provider designs its own tokenizer with distinct vocabulary sizes and training corpora. For example, OpenAI uses o200k_base (200k tokens), Anthropic uses a custom BPE (~65k tokens), Google Gemini uses SentencePiece with byte fallback, and DeepSeek uses a 128k BPE vocabulary. The exact same text will yield different token sequences and counts under each model family.

How is the API cost estimated, and does it include prompt caching?

Cost is calculated using published 2026 frontier pricing per million input and output tokens. Frontier models like GPT-4o and Claude 3.5 Sonnet support prompt caching discounts (typically 50% to 80% cheaper for cached prompt prefixes), which you can toggle in the cost simulator.

Does this tool send my text or documents to an external server?

No. 100% of tokenization, color-coded visual rendering, regex segmenting, and cost calculations run completely locally inside your web browser. Zero text, prompts, code snippets, or uploaded files ever leave your device.

What is the context window limit for modern 2026 models?

GPT-4o and DeepSeek V3/R1 support 128,000 tokens; Claude 3.7 Sonnet supports 200,000 tokens; while Google Gemini 1.5 Pro and 2.0 Flash support massive 1,000,000 to 2,000,000 token context windows. This tool's live Context Window Gauge visually indicates how much capacity your prompt consumes.