Unverified50% confidenceFactExact time
OpenAI reports cached input tokens in usage.prompt_tokens_details.cached_tokens, and the billing rate is lower; ignoring this causes costs to be overestimated.
1
Sources
50%
Confidence
Medium-term (~90 days)
Relevance
10/13/2026
First Seen
Valid until: 1/11/2027
Sources
Related Entities
Related Claims
UnverifiedCached input tokens are a discount mechanism offered by providers such as OpenAI for large repeated prefixes (such as system prompts, long documents, and few-shot examples); input tokens that hit the cache are billed at a lower rate, usually only about one-tenth of the standard input price.79% similarVerifiedOpenAI Prompt Caching can reduce the cost of repeated prefixes to 10%–25% of the original price.76% similarVerifiedOpenAI's API billing distinguishes between input tokens and output tokens, with output tokens typically priced higher.76% similarUnverifiedOpenAI provides a Prompt Caching mechanism for models such as Codex, which allows reuse of previously computed KV cache when the prefix token sequence of a request is identical to a prior one, reducing the billing price for that portion (typically 50% or even lower than the normal price).74% similarUnverifiedOpenAI typically charges 4–6 times more for output tokens than input tokens, because the computation involved in generation far exceeds that of comprehension.74% similar
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