Estimate/Retrieve the token usage and costs (prompt, completion, total) in C# with Azure OpenAI.

I would like to know if this is the best way to know how many tokens were consumed and can calculate costs.

I am not sure about costs, are those costs correct?

double costPer1KInput = 0.0015; // example for GPT-4o-mini input

double costPer1KOutput = 0.002; // example for GPT-4o-mini output

using Azure;

using Azure.AI.OpenAI;

var client = new OpenAIClient(

new Uri("https://YOUR-RESOURCE-NAME.openai.azure.com/"),

new AzureKeyCredential("YOUR-API-KEY"));

var options = new ChatCompletionsOptions()

{

DeploymentName = "gpt-4o-mini", // your deployment

Messages =

{

    new ChatRequestSystemMessage("You are a helpful assistant."),

    new ChatRequestUserMessage("Write a haiku about autumn.")

}

};

Response<ChatCompletions> response = await client.GetChatCompletionsAsync(options);

ChatCompletions completions = response.Value;

// Access token usage info

Console.WriteLine($"Prompt tokens: {completions.Usage.PromptTokens}");

Console.WriteLine($"Completion tokens: {completions.Usage.CompletionTokens}");

Console.WriteLine($"Total tokens: {completions.Usage.TotalTokens}");

Then I found this to evaluate costs:

double costPer1KInput = 0.0015; // example for GPT-4o-mini input

double costPer1KOutput = 0.002; // example for GPT-4o-mini output

double inputCost = completions.Usage.PromptTokens / 1000.0 * costPer1KInput;

double outputCost = completions.Usage.CompletionTokens / 1000.0 * costPer1KOutput;

double totalCost = inputCost + outputCost;

Console.WriteLine($"Estimated cost: ${totalCost:F4}");