AI Cost & Context Calculator
Estimate API cost and context-window usage for a prompt.
Inputs
Estimate
Enter a prompt and an expected output length to estimate cost.
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About AI Cost & Context Calculator
The AI Cost & Context Calculator estimates what a single API request will cost and checks that it fits within the model's limits. Paste your prompt, estimate how long the answer will be, and compare costs across models before you build.
How to use it
- Choose a model.
- Paste your prompt.
- Enter the number of output tokens you expect the model to generate.
- Review the input cost, output cost and total, along with any limit warnings.
Good to know
- Output tokens are usually priced several times higher than input tokens, so long answers dominate the cost.
- The tool warns you when the request would exceed the model's context window or its maximum output length.
- Prices are list prices per million tokens and can change. Discounts such as cached or batch pricing are not included.
- Supported models: GPT-4o, GPT-4 Turbo, GPT-4, GPT-3.5 Turbo, o1, o1-mini, GPT-4.1 and GPT-5.
Common questions
How do I estimate output tokens?
Run a few sample requests and check the usage figures your API returns, or use the Prompt Token Counter on a typical answer.
How do I reduce costs?
Shorten system prompts that repeat on every call, ask for concise answers, and use a smaller model for simple tasks.