Claude Opus 5 vs Claude Opus 4.8
Head-to-head technical comparison of intelligence, capabilities, and API pricing.
Which should you use?
Claude Opus 5 supersedes Claude Opus 4.8 in Anthropic's line-up, so this is an upgrade question rather than a bake-off.
Both bill at $5 per 1M input tokens, so there is no cost argument for staying.
Pick Claude Opus 5 when
- Higher composite index — 96.6 against 94.6, a gap of 2 points.
- Ahead on Arena Elo by 30 points (1493 vs 1463), which is outside the board's published confidence intervals.
- Stronger on MMLU-Pro: 95.7% against 94.5%.
Pick Claude Opus 4.8 when
On these measures Claude Opus 4.8 does not lead Claude Opus 5 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: Claude Opus 5 $0.052 · Claude Opus 4.8 $0.053 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.