GPT-5.6 Terra vs Grok 4.6
Head-to-head technical comparison of intelligence, capabilities, and API pricing.
Which should you use?
GPT-5.6 Terra and Grok 4.6 score within 0.1 points of each other on the composite index, which is too close to call a winner on capability alone.
Pick GPT-5.6 Terra when
- Stronger on MMLU-Pro: 93.5% against 93.1%.
Pick Grok 4.6 when
On these measures Grok 4.6 does not lead GPT-5.6 Terra anywhere, so pick it only for reasons outside this table — an existing integration, a region, or a contract.
Value per point of measured capability, at list input pricing: GPT-5.6 Terra $0.021 · Grok 4.6 $0.021 per index point. Run your own token mix through the token cost calculator — a comparison at list price ignores caching and batch discounts, which move real bills more than this gap does.
Where these numbers come from
Figures as of 2026-09-07. Arena Elo and pricing are read from the public board and each vendor's own pricing page; see the full leaderboard for all 34 models and which columns are measured rather than estimated, or the benchmark matrix for scores benchmark by benchmark.