Token Count Calculator
Estimate how many tokens your text uses for GPT-4, Claude, Gemini, LLaMA and other language models. Calculate API costs, check context window usage, and optimize your prompts.
GPT-4 / GPT-4o
Context window: 128.0K tokens • Tokenizer: cl100k_base • ~4 chars/token
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Estimate Token Count for AI Models
Large language models (LLMs) like GPT-4, Claude, and Gemini process text as tokens—subword units that affect API pricing and context limits. Our calculator estimates token counts across popular models, helping you optimize prompts and predict costs.
What Are Tokens in AI?
Tokens are the fundamental units that LLMs use to process text. A token can be a word, part of a word, or even punctuation. English text averages about 4 characters per token, meaning 'tokenization' might split into 'token' and 'ization'. Different models use different tokenizers (BPE, SentencePiece), affecting exact counts.
Token Estimation Formula
Tokens ≈ Characters ÷ 4 (for English text)Why Token Counting Matters
API Cost Management
LLM APIs charge per token. GPT-4 costs ~$0.01 per 1K input tokens. Knowing your token count helps budget API usage and avoid unexpected costs.
Context Window Limits
Each model has a maximum context window (GPT-4: 128K, Claude 3: 200K, Gemini: 1M tokens). Exceeding this limit truncates your input or causes errors.
Prompt Optimization
Shorter prompts cost less and often perform better. Token counting helps identify verbose sections to trim without losing meaning.
Response Planning
Output tokens also count toward limits and costs. Reserve space in your context window for model responses.
How to Use This Calculator
Frequently Asked Questions
Each model uses proprietary tokenizers with different vocabularies. GPT-4 uses cl100k_base, Claude uses its own BPE tokenizer. Our estimation uses character ratios that are accurate within 5-10% for English text. For exact counts, use official libraries like OpenAI's tiktoken.