AI Token & API Cost Estimator
Paste your raw text, code snippets, or system prompts below and select your intended task. This tool will calculate the exact input token count and estimate your total costs (input + output) across leading models from OpenAI, Anthropic, and Google. There is a 5 million character (~1.25M tokens) submission limit.
How Tokenization Works
What is a token? Large Language Models process text in chunks called tokens. A token can be an entire word, a syllable, or just a single character. A useful rule of thumb for standard English text: one token is roughly 4 characters, or about 0.75 words.
Why do costs vary? Different providers use distinct model architectures and pricing strategies based on the compute required. Frontier reasoning models like Claude Opus 4.6 and GPT-5.2 carry a premium over standard models like Claude Sonnet 4.6 or Gemini 3.1 Pro, which are optimized for everyday throughput at lower cost.
How are output tokens estimated? This tool estimates output tokens based on the task type you select — for example, summarization targets ~15% of your input length, while translation targets ~100%. These are heuristics, not guarantees. Actual output length depends on your prompt wording, the model's behavior, and any max_tokens limits you set in your API call.
Tokenizer note: Token counts are calculated using OpenAI's cl100k_base encoding via the tiktoken library. This is a close approximation for GPT-5.2 and a reasonable heuristic for Anthropic and Google models, which use their own internal tokenizers. Counts may vary by a few percent across providers on the same input.
This tool was created by Ben Crittenden, an IT professional with experience in web development, systems administration, and project management.