September 23, 2026
Paying for AI will get cheaper: the same GPQA Diamond result now costs 725 times less
On September 22, Epoch AI estimated that achieving 75% on GPQA Diamond became 725 times cheaper in less than 18 months. OpenAI o3 achieved it for about $0.30 per question on January 31, 2025. GPT-5.6 Luna delivered the same result for $0.0004.
Previously, teams chose a model for a given result and kept using it. Epoch AI now calculates the minimum cost for each task separately: since 2023, it has fallen by an average of 47% per quarter, or 13 times per year.
Switching wins. The calculation assumes that users choose the most cost-effective model every time. Those who switch less often do not capture all of those savings.
The study data and code are published on GitHub, and the report page includes interactive charts and tables.
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