Up to four models

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Side by side on the same independent tests, with price and context. The link in your address bar shares this exact comparison.

Claude Opus 5.5GPT-6 Astra

Next to Claude Opus 5.5

Presets

Claude Opus 5.5

200188–211

WeightsClosed

ReleasedSep 2026

Price in / out$4.0 / $20

Context1M

Core tests taken4 of 8

GPT-6 Astra

197186–209

WeightsClosed

ReleasedSep 2026

Price in / out$10 / $50

Context1.05M

Core tests taken5 of 8

Claude Opus 5.5 and GPT-6 Astra are too close to call (2 points apart, within the uncertainty), ahead on 1 of 4 shared core tests, and costs 2.5× less.

Test by testindependent results · Epoch AI

Claude Opus 5.5GPT-6 Astra

Only tests that at least two of these models have taken. Bold rows are the core tests shown on every profile; all of these results inform the index score. Task length (METR) is listed below the chart because it is a duration, not a percentage.