How is AI API cost calculated?

AI APIs charge separately for input tokens (your prompt) and output tokens (the response). Total cost = (input tokens × input rate) + (output tokens × output rate). Rates are expressed per million tokens.

Why are input and output tokens priced differently?

Generating output tokens requires more compute than processing input tokens. Models cache input tokens and process them in parallel, but output tokens are generated sequentially — making them more expensive.

Are token counts accurate?

This calculator uses word-based approximations (~1.3 tokens per word). For exact billing, use the official tokenizer libraries (tiktoken for OpenAI, Anthropic token counting API). Actual charges may differ by 5-15%.

AI API Cost Calculator

Estimate AI API costs for GPT, Claude, Gemini, and LLaMA.

Model

Input text

0 input tokens detectedOutput estimated at 50% (0 tokens)

Model pricing

Input price$0.000003 / token$2.50 / 1M tokens

Output price$0.000010 / token$10.00 / 1M tokens

Cost estimate

Per request$0.000000

Per 1K requests$0.000000

Daily (100 req)$0.000000

Monthly est.$0.000000

0 input tokens0 output tokens

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FAQ

How is AI API cost calculated?: AI APIs charge separately for input tokens (your prompt) and output tokens (the response). Total cost = (input tokens × input rate) + (output tokens × output rate). Rates are expressed per million tokens.
Why are input and output tokens priced differently?: Generating output tokens requires more compute than processing input tokens. Models cache input tokens and process them in parallel, but output tokens are generated sequentially — making them more expensive.
Are token counts accurate?: This calculator uses word-based approximations (~1.3 tokens per word). For exact billing, use the official tokenizer libraries (tiktoken for OpenAI, Anthropic token counting API). Actual charges may differ by 5-15%.

Calculate the cost of AI API calls across GPT, Claude, Gemini, and LLaMA models. Paste text to auto-count tokens, or enter token counts manually. See per-request, per-1K-request, daily, and monthly estimates.