Subscription or API: which is cheaper

A chat subscription's monthly price against the same use paid by the token through the API: at the cheapest seller of the model and at the model maker's own API, and how many messages a day make the subscription pay off. How to use it

Claude Pro: $20.00 a month, from claude.com/pricing (checked daily).

Claude Sonnet 5.5

At your use the API is cheaper: $11.52 a month against $20.00 for the subscription.

Through the API	One message	A month	Subscription pays off from
cheapest seller: cometapi	$0.0096	$11.52	69.4 messages a day
the maker's own API: anthropic	$0.012	$14.40	55.6 messages a day

Formula: (input tokens × input price + output tokens × output price) × messages a day × 30. A chat app resends the conversation with each message, so input grows with a long chat. Not counted: the subscription's extras (apps, image generation, voice, limits) and API caching, which lowers the API cost.

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