Is Claude or OpenAI prompt caching cheaper in practice?
Historical consensus 2026-08-18Active
Runs Weekly on Tuesday at 09:00 (Europe/Berlin)LastNext
Movement at this check
Changed since last check
The answer itself held, but the models now agree more than in the recent checks (+26 pts). Refined the pricing comparison to clarify that both providers offer similar cache read discounts (~90%) and that total cost differences often stem from underlying base model prices, while maintaining the same core conclusions regarding which provider to choose for different workload patterns.
Short answer: usually OpenAI is cheaper in practice if you compare similar-capability models and you get decent cache hits; Claude can be cheaper in high-reuse, stable-prefix workflows, especially when its explicit caching fits your request pattern well.
Why:
The cache discount itself is broadly similar on current flagship-style offerings: cached reads are around 90% cheaper than normal input for both, and cache writes are typically 1.25× input for short-lived caching; Claude also offers a 1-hour cache at 2× input.anthropicopenai
So the real cost difference usually comes from the base model price and how often you actually hit the cache, not the caching mechanism alone.anthropic
In many cases, OpenAI’s underlying models are a bit cheaper, so the total bill can be lower even with similar caching terms.anthropic
Claude can win when you have large, stable prefixes reused many times within the cache window, because the 90% read discount amortizes the write cost quickly.anthropicopenai
Practical rule of thumb:
Choose OpenAI if you want lower risk, simpler automatic caching, or a cheaper comparable model.anthropicopenai
Choose Claude if you have very repetitive prompts, stable system/tool/doc prefixes, and high cache hit rates—especially in agentic or document-heavy workflows.anthropicopenaiopenai
One important caveat: if your prompts are dynamic or cache hits are unreliable, the cheaper option is often the one with the lower base model price, because cache savings may not materialize.anthropicopenai
So, in practice: OpenAI is often cheaper by default; Claude can be cheaper when caching is highly optimized and frequently reused.
Differences
The 3 models broadly agree – no notable differences found.
Best answerOpenAI
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Restated, not moved: The consensus shifted from stating OpenAI is usually cheaper in default practice to clarifying that neither is universally cheaper. It adds explicit mathematical breakdowns, details on OpenAI's tiered cache read discounts (0.1x to 0.5x) vs. Claude's write premiums/5-minute window, and broader workload nuances.
Refined the pricing comparison to clarify that both providers offer similar cache read discounts (~90%) and that total cost differences often stem from underlying base model prices, while maintaining the same core conclusions regarding which provider to choose for different workload patterns.
3 AI models
answered this question independently on 2026-08-18. A judge from a different model family
then cross-checked the answers, scored how far they agree and flagged where they differ. The question is re-checked weekly, and every earlier version stays on this page.
AI models can make mistakes – verify important information against the sources above.
