The Model Index
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.

Next to Claude Sonnet 5.5
Presets
Claude Sonnet 5.5
193182–205
WeightsClosed
ReleasedSep 2026
Price in / out$2.0 / $10
Context1M
Core tests taken3 of 8
GPT-6.1 Sol
184168–200
WeightsClosed
ReleasedSep 2026
Price in / out$2.0 / $10
Context1.05M
Core tests taken3 of 8

Claude Sonnet 5.5 and GPT-6.1 Sol are too close to call (9 points apart, within the uncertainty), ahead on 2 of 3 shared core tests, at a similar price.

Test by testindependent results · Epoch AI

Claude Sonnet 5.5GPT-6.1 Sol

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.