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SubVerdict Reviews
Buying guide · Checked September 2026

Is the API cheaper than a ChatGPT Plus or Claude Pro subscription?

If you ask a handful of questions a day, yes, and not by a little. At the per-token rates OpenAI, Anthropic and Google publish, 150 short exchanges a month on a mid-range model cost under a dollar, against $20 for the plan. The picture changes once you keep long conversations going, paste in documents or reach for the most expensive models: two long chats a day on a flagship model already cost more than the subscription.

By the SubVerdict desk Published 29 September 2026 Last verified 29 September 2026 ~7 min read
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Two different bills

A subscription is a flat monthly fee for an app. OpenAI's pricing documentation for ChatGPT Work and Codex lists the Plus plan at $20 a month and Go at $8 a month. Anthropic's pricing page puts Claude Pro at "$20 if billed monthly", or $17 a month on the annual plan with $200 billed up front, and notes that "Prices shown don’t include applicable tax." Google's plans page, shown for the United States, lists Google AI Pro at $19.99 a month and Google AI Plus at $4.99. Prices can differ by country, so go by what the official page shows for yours.

The API is metered. You pay for tokens, the small pieces of text a model reads and writes. Anthropic's rough guide is that "1 token is approximately 4 characters or 0.75 words in English"; Google's is that "100 tokens is equal to about 60-80 English words." Everything you send counts as input and everything the model writes back counts as output, and output is the expensive half.

On Claude, the two are separate purchases. Anthropic says plainly that "A paid Claude subscription enhances your chat experience but doesn't include access to the Claude API or Console", and that anyone who wants both will "need to sign up for a paid Claude plan and separately set up Console access for API usage."

The per-token rates we used

Read from each provider's API pricing page on 29 September 2026. All figures are US dollars per 1 million tokens.

API prices per million tokens, September 2026
ModelInputOutputRough tier
GPT-6 Luna (OpenAI)$0.10$0.50Budget
Gemini 3.8 Flash (Google, to 31 Dec 2026)$0.75$3.75Budget
Claude Haiku 4.5 (Anthropic)$1$5Budget
GPT-6 Sol (OpenAI)$2.00$10.00Mid-range
Claude Sonnet 5.5 (Anthropic)$2$10Mid-range
Claude Opus 5.5 (Anthropic)$4$20Upper
GPT-6 Astra (OpenAI)$10.00$50.00Flagship

OpenAI's table splits its rates into short-context and long-context columns, and many rows show no long-context price; the figures above are the short-context input and output columns. OpenAI charges 10% more for FedRAMP, and for regional data-residency processing on eligible models released on or after 5 March 2026. Anthropic's figures are its "Base input tokens" and "Output tokens" columns, where "MTok" means a million tokens. Google's Flash rates are paid-tier prices "through December 31, 2026"; from 1 January 2027 the same page lists $1.50 input and $7.50 output, and its output price is "including thinking tokens". The "rough tier" column is our own shorthand.

One more wrinkle on Claude. Anthropic says "Claude 4.7 and later models" use a newer tokenizer that "produces approximately 30% more tokens for the same text", so the same words can come to more tokens on those models than on older ones.

A light month: five questions a day

Our worked example is a short exchange: a 200-token question (about 150 words by Anthropic's rule of thumb) and a 500-token answer (about 375 words). Five of those a day for 30 days is 150 exchanges. The cost of that month, and how many such exchanges $20 would cover instead:

Cost of 150 short exchanges a month, and exchanges per $20
Model150 exchangesExchanges per $20
GPT-6 Lunaabout $0.04about 74,000
Gemini 3.8 Flash (2026 rate)about $0.30about 9,900
Claude Haiku 4.5about $0.41about 7,400
GPT-6 Sol or Claude Sonnet 5.5about $0.81about 3,700
Claude Opus 5.5about $1.62about 1,850
GPT-6 Astraabout $4.05about 740

For a reader who uses AI like a search box, the metered bill stays well under the plan price even on the flagship.

Where the maths flips: long conversations

A chat app keeps the conversation going for you. On the API, the history is part of what you pay for. Anthropic's documentation says its Messages API "is stateless, which means that you always send the full conversational history to the API", and OpenAI's says that even when you chain responses, "all previous input tokens for responses in the chain are billed as input tokens in the API." Every follow-up pays again for everything said so far.

Take the same 200-token questions and 500-token answers as a single ten-turn conversation. By the tenth turn you are sending 6,300 tokens of history plus the new question, and across the whole thread the input adds up to 33,500 tokens against 5,000 of output. On GPT-6 Sol or Claude Sonnet 5.5 that one thread costs about $0.12, more than double what ten separate questions would. These sums charge the resent history at the standard input rate; OpenAI's table also lists a cached-input rate and Anthropic's a cache-hit rate, both $0.20 per million for these two models, which the sums leave out. Two such threads a day for a month:

  • GPT-6 Sol or Claude Sonnet 5.5: about $7.02. The $20 plan only comes out cheaper past roughly 170 ten-turn threads a month.
  • Claude Opus 5.5: about $14.04. Break-even is around 85 threads a month.
  • GPT-6 Astra: about $35.10, already well past a $20 plan. Break-even is around 34 threads, about one a day.
  • Claude Haiku 4.5, Gemini 3.8 Flash, GPT-6 Luna: about $3.51, $2.63 and $0.35.

A 20-turn thread on Sonnet 5.5 comes to about $0.37, against about $0.23 for two ten-turn threads covering the same questions, so starting a fresh chat when the topic changes is the cheapest habit on the API. Pasted material works the same way: at 0.75 words per token, a 3,000-word document is about 4,000 input tokens, and it is sent again with every question you ask about it.

What the per-token price doesn't show

You need somewhere to type. An API key is not an app. Anthropic describes its Console as "our developer platform providing API keys and access to Claude models for building applications and integrations", with a playground billed from the same credits; Google's free tier lists Google AI Studio access. Anything beyond that means code or an app you trust with your key.

Credits are prepaid, and on Claude they expire. Anthropic says API and playground usage "is billed through prepaid usage credits", that "If you run out of credits, you can no longer call the API or use the playground until you add more", and that "Credits expire one year from the purchase date" and "All credit purchases are non-refundable." For a light user that argues for topping up small amounts rather than a large block. New users "receive a small amount of free credits to test the API."

Caps are yours to set. OpenAI lets you enforce a hard spend limit for an organisation or a project, but "Spend alerts do not enforce a cap", and even a hard limit is "not instantaneous, so recorded spend can slightly exceed the configured amount." On Anthropic, auto-reload "purchases additional credits automatically when your balance falls below a threshold you set", which is convenient and also the setting that removes the natural stop.

Gemini's free API tier has a data price. Google's Gemini API has a free tier with "Free input & output tokens" and "Limited access to certain models", and its pricing table marks free-tier content as "Used to improve our products": Yes on the free tier, No on the paid one. If that matters to you, our guide to which AI plans train on your work covers the consumer apps.

The apps bundle more than the model. Anthropic calls its paid plans and the Console "separate products designed for different purposes": the plans give "access to Claude on the web, desktop, and mobile", and the Pro card adds Projects, "Claude Design, Slides, Docs" and "Claude in Chrome and Microsoft 365" to the free plan. Claude Code can go either way: Anthropic says that for heavy coding sessions "you can also switch to pay-as-you-go API credits through a Console account".

You don't have to choose once

On Claude's paid plans, when you hit a limit you can "turn on usage credits to keep working at standard API rates", so heavy weeks spill over into metered billing instead of forcing an upgrade. For ChatGPT Work and Codex, which share one usage allowance, OpenAI's pricing documentation says "ChatGPT Plus and Pro users who reach their usage limit can purchase additional credits to continue working without needing to upgrade their existing plan."

If you do subscribe, the annual vs monthly comparison covers whether prepaying a year is worth it, and our AI pricing comparison puts the subscription tiers side by side.

Our pick by type of user

  • A few standalone questions a day: the API, on a mid-range model. Expect well under $5 a month.
  • Long working sessions most days: the subscription. Ten-turn threads on a mid-range model reach $20 at about five or six a day, and sooner on upper-tier models.
  • Heavy use of a flagship model: per-token flagship rates overtake $20 at about one ten-turn thread a day. Check which models a plan includes on its own page before you switch.
  • Anyone who works in Claude's Projects or its Design, Slides and Docs tools: the subscription, where Anthropic lists them as plan features.

FAQ

Does Claude Pro include API access?

No. Anthropic's help centre says a paid Claude subscription “doesn't include access to the Claude API or Console.” If you want both, you keep the plan and set up a Console account separately, with its own prepaid credits.

Is the OpenAI API cheaper than ChatGPT Plus?

For light use, by a wide margin. At GPT-6 Sol's listed rates of $2.00 input and $10.00 output per million tokens, 150 short questions a month come to about $0.81, against $20 a month for Plus. Two ten-turn conversations a day for a month on the same model come to about $7, with the resent history charged at the full input rate. On GPT-6 Astra the same two conversations a day for a month cost about $35.

Is the Gemini API free?

There is a free tier. Google's pricing page lists free input and output tokens, limited access to certain models, and content used to improve Google's products. The paid tier bills per token and lists content as not used to improve its products.

Sources

All read on 29 September 2026, English versions. The worked costs above are our own arithmetic on these published rates.

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