Subscription or pay-as-you-go API: price the way you actually work

The scene

You are deciding between a monthly chat-app plan and API prepaid credit, or you already have both bills and want to know which to keep.

Tools involved

What they did

1. Write down how you actually work each week: mostly in the official chat window, or mostly from your own scripts, editor, or office tools.
2. If you almost always work in the official window, start with the subscription list price. Anthropic’s official pricing page lists Claude Pro at $20 monthly, or $17 per month when you prepay $200 annually; Max is $100 per month including $100 a month in API credits; Ultra is $200 per month including $200 a month in API credits. ChatGPT’s official pricing page likewise lists Free, Go, Plus, Pro, and other plans; Pro was marked $100 in that page’s content on 10 Nov 2026, and the other dollar amounts should be read from the live official page.
3. If your own programs are doing the calling, estimate against API rates. Multiply weekly input and output millions of tokens by the official unit price. Claude Sonnet 5.5 is $2 / $10. OpenAI gpt-5.4-mini standard is $0.75 / $4.50. If a job can wait, Batch may help: gpt-5.4-mini Batch is about half the standard rate.
4. Count bundled API credit. Claude Max and Ultra officially include $100 and $200 a month in API credits, which changes whether a separate API top-up is worth it. The exact redemption rules are in your account documentation.
5. Keep the bill that matches the work: a subscription for everyday chat in the official app, an API for automation. Running both without a clear split usually means paying twice.

Copyable prompt

Here is how I work each week: [describe chat-app use vs API/automation], and here are official prices I copied on [date]. Help me decide what to keep. Show a simple monthly estimate from those copied numbers only. If my usage notes are too vague to estimate, ask up to three questions instead of inventing a figure. Do not promise that one option will always be cheaper.

Rewritten here for you to try; not a verbatim excerpt from elsewhere. What it asks：Give the model your usage pattern and the official prices you copied that day, and ask for a rough estimate from those numbers only.

Things to watch

Which option costs less depends on real volume, whether you use the subscription allowance, whether you can use Batch or cache, and whether official prices change. This article makes no guarantee. Dollar prices for ChatGPT plans other than Pro are not invented here, because they were not reliably readable from the static HTML. Team, education, and tax rates are not included.