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Prompt Token Estimator

Estimate prompt tokens from pasted text, character count, messages, overhead tokens, and model-call volume.

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Calculator

Inputs

Text to estimate. It stays in your browser.

Approximate characters represented by one token.

Live output

Results

Estimated Prompt Tokens
1,073
Character Count
92
Monthly Prompt Tokens
53,650,000
Text Tokens
23

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Assumptions

  • This is an approximation, not exact tokenization.
  • Different models and languages tokenize differently.
  • Prompt text is not uploaded.

Sensitivity preview

Characters per Token -10%: Estimated Prompt Tokens 1,076

Characters per Token Current: Estimated Prompt Tokens 1,073

Characters per Token +10%: Estimated Prompt Tokens 1,071

Logic: Text tokens = character count / characters per token. Estimated prompt tokens = text tokens + message overhead + extra context tokens. Monthly prompt tokens = estimated prompt tokens * monthly requests.

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About this Prompt Token Estimator

Prompt cost and context-window fit depend on token count. This estimator provides a transparent approximation from text length and overhead.

Who this calculator is for

  • Prompt engineers estimating context size.
  • Developers budgeting LLM calls.
  • AI teams comparing prompt templates.

When to use it

  • Estimate prompt tokens before calling a model.
  • Add chat message overhead and tool instructions.
  • Calculate monthly prompt token volume.

How to use this calculator

  1. Paste prompt text or leave the default sample.
  2. Adjust characters per token for your language/content type.
  3. Add message overhead and monthly requests.
  4. Review estimated tokens and monthly token volume.

Key assumptions

  • This is an approximation, not exact tokenization.
  • Different models and languages tokenize differently.
  • Prompt text is not uploaded.

Accuracy and testing

Review formula sources, default test cases, assumptions, unit handling, rounding rules, and changelog for this calculator.

View accuracy page

How this calculator works

Estimated text tokens = character count / characters per token. Total prompt tokens = text tokens + message overhead + extra context tokens.
Text tokens = character count / characters per token. Estimated prompt tokens = text tokens + message overhead + extra context tokens. Monthly prompt tokens = estimated prompt tokens * monthly requests.

Inputs explained

Prompt text

Text to estimate. The calculator uses character length, not a model tokenizer.

Characters per token

Approximation factor; 4 is a common rough English estimate.

Overhead tokens

System messages, chat wrappers, tool schemas, or retrieved context.

Understanding your results

Use estimated prompt tokens as a planning number, then verify with a provider tokenizer for exact billing or context limits.

Example scenarios

Support prompt

A 6,000-character prompt at 4 characters/token is about 1,500 text tokens before overhead.

Key Features

  • Instant Calculation
  • Private & Secure
  • Mobile Optimized

Tips & Best Practices

  • Use a tokenizer for final production limits.
  • Track retrieved context separately from static system prompts.
  • Estimate output tokens with the LLM token cost calculator.

Frequently Asked Questions

Is this exact?
No. It estimates tokens from characters. Exact token counts require a tokenizer for the specific model.
Does it send my prompt anywhere?
No. It calculates from the text in your browser.
Are my AI usage assumptions stored?
No. The calculation runs locally in your browser and does not upload your inputs.