AI Model Stack Cost Breakdown: January 2026 API Usage and Billing (Subscription

Hello, I am ttokunaga, an individual developer.

When integrating AI models into development or daily tasks, isn't it often that costs become unclear when everything is covered by APIs (pay-as-you-go), leading to anxiety?

Currently, I operate with a hybrid configuration: "Maximize the use of monthly fixed subscriptions (such as ChatGPT Plus or Claude Pro), and only hit APIs when message limits are reached or for specific automation tasks."

This time, I will review the January 2026 API billing results, comparing them with last month's figures, along with dashboard screenshots.

📊 Total Usage Amount, Cost Trend, and Total Token Count

• Total API usage amount this month: $231.68 (approx. 34,800 JPY) - Total API usage amount last month: $184.85 (increase from previous month: +$46.83) - Cumulative API usage amount: $763.86 (since October 2025) - Total token count this month: approx. 257 million tokens - Input token count: 254,323,713 tokens - Output token count: 2,952,920 tokens

January was primarily centered on the use of Anthropic API. I used it for end-of-term reports and university test preparation, in addition to advancing personal production using Claude Code.

In terms of token count alone, it is less than last month, but costs are increasing due to unit price effects. It was a month where end-of-semester output and personal production overlapped, leading to increased reliance on Claude-based models.

🥇 Anthropic API

• Main Usage: End-of-term reports, test preparation, personal production with Claude Code, refactoring - Tokens consumed this month: 257,276,633 tokens - API cost this month: $231.68

💡 Usage Feelings & Impressions

Claude-based models provide reassurance in situations where I want to capture the intent of the code. In personal production using Claude Code, it was quite convenient to consult on revision plans spanning multiple files and how to proceed with implementation.

Additionally, for end-of-term reports and test preparation, I received explanations for unclear parts or had my report logic structure checked. They are reliable in situations where naturalness of text is prioritized.

This is the usage amount of Anthropic API in January 2026

The cost of using Anthropic API in January 2026 was $231.68

💡 Summary

The API billing for January 2026 was $231.68. Due to the overlap of end-of-term reports, test preparation, and personal production with Claude Code, the use of Anthropic API increased.

While it is fortunate that high-performance models can be used via APIs, in months where heavy consultations are thrown repeatedly, separating tasks from being completed on the subscription side becomes more important.