What are the costs for uploading and processing a 100,000-word file with the Assistants API?

Below is an explanation of the billing aspects related to file uploads and token processing:

File Upload vs. API Calls

• Uploading a File:
  When you upload a file (e.g., one containing 100,000 words) to use with APIs such as fine-tuning or the Assistants API, the upload itself does not incur immediate per-token costs. Instead, the file is stored and then used for subsequent API calls.

• Processing the File:
  Costs come into play when you later reference or process the file’s contents (e.g., fine-tuning a model or generating completions). In these cases, you are charged based on the number of tokens that are sent as input and generated as output in each API call.

Token Billing Details

• Token Calculation:
  As a rough rule of thumb, 1 token is approximately 4 characters or 0.75 words for English. Therefore, a file with 100,000 words translates to roughly 133,333 tokens. However, this conversion is only used for estimating costs when the file’s contents are processed by the API.

• When You Are Charged:

  • Fine-tuning: When using the file for fine-tuning, the tokens read from the file during the training process are counted as input tokens.
  • Text Generation Requests: For completion or chat-based API calls, you pay for both the input tokens (which may include parts of the file data) and the output tokens generated by the API.

• Pricing Model:
  OpenAI’s pricing is based on a pay-as-you-go model where you are billed per 1,000 tokens processed. The pricing details (which may vary for input vs. output tokens) can be found on the OpenAI pricing page.

Summary

• Simply uploading the file doesn’t incur token charges.
• Charges occur during API calls that use that file’s content.
• Both the tokens you send (input) and the tokens you receive (output) are counted against your usage.
• You should estimate your costs based on how many tokens (estimated from your file's content) will be processed in your application’s API calls.

This separation helps manage costs, as you can decide when and how to use the uploaded data in your application while keeping close track of your token utilization.