How is AI priced?
A simple breakdown of pay-as-you-go pricing
Key takeaway
AI API pricing is generally pay-as-you-go, like electricity or gas. The key detail is that output (the text you receive) costs more than input (the text you send).
Pay for what you use
Instead of a fixed monthly amount, you pay according to the number of tokens processed. More usage means a higher bill; less usage means a lower one.
An electricity meter
Electricity used (kWh) × unit price. Lower usage means a smaller usage bill.
AI token billing
Tokens used × unit price. The principle is exactly the same.
Volume makes the difference
Long documents and large processing volumes add up.
Input and output have different prices
This is the first point that can be confusing. The text you send to AI and the text it returns are billed separately, at different rates.
Input tokens (INPUT)
Text you send to AI: instructions, questions, and reference material. The unit price is relatively low.
Output tokens (OUTPUT)
Text generated and returned by AI: answers, summaries, and drafts. The unit price is higher, often three to six times the input rate.
Pricing tables use dollars per million tokens
The providers compared here list token prices in this unit. Once you understand it, you can compare their tables on the same basis.
| Notation | Meaning |
|---|---|
| $2.00 / 1M tokens | One million tokens cost about USD 2 (approximately JPY 320) |
| 1M | One million tokens (roughly 600,000–700,000 Japanese characters) |
| input / output | Separate unit prices for input and output |
Imagine a restaurant charging separately for ingredients you bring in (input) and the prepared dish it serves (output). It makes sense that the dish requiring preparation costs more.
Frequently asked questions
How does AI pricing work?
With usage-based pricing, you pay for what you use instead of a fixed monthly amount. Input and output have separate prices, and output usually costs more.
How do I read the pricing table?
Look for USD per one million tokens. A key way to control cost is to pay attention to output: how much you ask AI to write.
Based on the official pricing pages of OpenAI and Google AI, as of June 2026. Prices, model names, and specifications can change; check current official information before deciding. Estimates use USD 1 = JPY 160 and approximately 1.5 tokens per Japanese character. They are illustrative Japan-market references, not quotations or estimates for English-language text. This series does not recommend any particular service. Contact sales to confirm current product pricing, delivery, warranty, and support for your country.
Company, product, and service names mentioned are trademarks or registered trademarks of their respective owners.