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LLM Prompt Token Counter & Words to Tokens Calculator

Paste any prompt, document, or code block to estimate BPE token count, word count, characters per token, and context window headroom for GPT-4o, Claude, and Gemini.

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Estimated Tokens (GPT / Claude)
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Words
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Characters (with spaces)
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Tokens / Word

Context window usage

8K Context (8,192 tokens)0%
32K Context (32,768 tokens)0%
128K Context (GPT-4o / DeepSeek)0%
200K Context (Claude Sonnet / Opus)0%
1M Context (Gemini Pro / Flash)0%
Est. Single-Spaced Pages0 pages

More writing & AI tools

Words to tokens conversion chart (100 to 200,000 tokens)

Quick reference for prompt engineers, developers, and writers working with GPT-4o, Claude, Gemini, and Llama.

Modern large language models tokenize text using Byte-Pair Encoding (BPE). In standard English prose, 1 token equals roughly 4 characters or 0.75 words (meaning 100 tokens ≈ 75 words, and 100 words ≈ 133 tokens). Punctuation, indentation, JSON keys, and non-Latin characters consume additional tokens per word.

Token Count English Word Count (~0.75 w/tok) Character Count (~4 chars/tok) Pages (Single-Spaced) Typical Document / Context Size
100 tokens~75 words~400 characters0.15 pagesShort paragraph, email hook, or system instruction
500 tokens~375 words~2,000 characters0.75 pagesStandard cold email or short blog intro
1,000 tokens~750 words~4,000 characters1.5 pagesShort article or detailed few-shot prompt
2,000 tokens~1,500 words~8,000 characters3 pagesStandard SEO blog post or 10-minute YouTube script
4,096 tokens (4K)~3,070 words~16,380 characters6 pagesLong-form guide or academic essay
8,192 tokens (8K)~6,140 words~32,760 characters12 pagesWhite paper or technical specification
32,768 tokens (32K)~24,500 words~131,000 characters49 pagesNovella or multi-chapter report
128,000 tokens (128K)~96,000 words~512,000 characters192 pagesFull-length non-fiction book (GPT-4o / DeepSeek window)
200,000 tokens (200K)~150,000 words~800,000 characters300 pagesLarge codebase or 500-page book (Claude context window)

How Byte-Pair Encoding (BPE) tokenization works across languages and code

Unlike traditional word processors that split text strictly on whitespace, modern transformer models (including OpenAI’s cl100k_base and o200k_base vocabularies, Anthropic’s Claude tokenizer, and Google’s SentencePiece models) break text into subword units called tokens. High-frequency English words with a leading space (such as " the" or " function") are encoded as a single integer ID, whereas compound technical terms or inflected words (such as "tokenization" → ["token", "ization"]) split into multiple subwords.

Because tokenizer vocabularies are trained predominantly on English prose and common source code, token-to-word and token-to-character ratios vary substantially by content type:

Content Type / Script Avg. Tokens per Word Avg. Characters per Token Why Token Density Changes
Standard English Prose~1.30 – 1.35 tokens/word~3.8 – 4.2 chars/tokenMost common root words and suffixes map to single BPE vocabulary entries
Spanish / German / Portuguese~1.55 – 1.85 tokens/word~3.0 – 3.5 chars/tokenDiacritics (á, ñ, ü, ç) and German compound nouns split into extra subword pieces
Python / JavaScript / TypeScript~1.80 – 2.40 tokens/word~2.5 – 3.2 chars/tokenBrackets, operators, camelCase identifiers, and indentation spaces add token overhead
Minified vs. Pretty JSON~2.20 – 3.10 tokens/item~2.0 – 2.8 chars/tokenRepeated quotes, colons, braces, and 2-space indentation inflate token count by 15%–30%
Chinese / Japanese / Korean (CJK)1.0 – 1.8 tokens/character~0.6 – 1.1 chars/tokenMulti-byte UTF-8 ideographs often require 1 to 2 BPE tokens per single character

Context window budgeting: Why 80% utilization beats 99%

Even when working with a 128K, 200K, or 1M token context window, filling the window to capacity introduces three practical engineering bottlenecks: output reservation (total context equals input_tokens + max_completion_tokens, so leaving too little headroom truncates responses mid-sentence), “Lost in the Middle” attention dilution (models recall instructions at the very beginning and very end of a prompt with higher accuracy than facts buried in the middle 50%), and Time-to-First-Token (TTFT) latency. Stripping redundant Markdown, whitespace, and boilerplate with the AI Text Cleaner before prompting routinely cuts input token usage by 10%–25%.

Tokenizer differences & estimation boundaries

Different model families use distinct subword vocabularies: OpenAI GPT-4o uses o200k_base (200,000 vocabulary entries), GPT-4/3.5 uses cl100k_base (100,277 entries), Anthropic Claude uses its proprietary BPE vocabulary, and Google Gemini uses SentencePiece. Because downloading multi-megabyte vocabulary tables would slow down browser startup, TextScope uses a deterministic client-side BPE heuristic calibrated across English prose, European diacritics, source code punctuation, and CJK UTF-8 sequences. Estimates typically fall within ±3% to 6% of exact API billing counts; for hard billing cutoffs, leave a 5% safety buffer below your target context limit.

Frequently asked questions

How many tokens is 1,000 words?

In standard English prose, 1,000 words is approximately 1,300 to 1,350 tokens (at the standard ratio of 1 token ≈ 0.75 words or 4 characters). Conversely, 1,000 tokens is roughly 750 English words.

What is the formula to convert words to LLM tokens?

For English text, multiply your word count by 1.33 (Tokens ≈ Words × 1.33) or divide total characters (including spaces) by 4 (Tokens ≈ Characters ÷ 4). Source code, JSON, and non-Latin scripts such as Japanese, Korean, or Chinese consume more tokens per character.

How many words fit in a 128K or 200K token context window?

A 128,000-token context window holds roughly 96,000 English words (about 300–350 book pages). A 200,000-token context window holds roughly 150,000 English words (about 500 book pages).

Is my prompt uploaded to any server when counting tokens?

No. All token, word, and character calculations run 100% locally in your web browser, making it safe for proprietary code and confidential system prompts.