WhichAI / Compare / Claude Sonnet 5 vs GPT-5.5

Claude Sonnet 5vsGPT-5.5

GPT-5.5 scores higher on the September 8, 2026 index. Full context below: price, context window, strengths and honest limits. Verified September 8, 2026.

Claude Sonnet 5

GPT-5.5

Provider

AA index

55.3

56.3

Released

n/a

2026-04

Context

n/a

Price $/1M

$3 / $15

n/a

Access

FREE tier of claude.ai · API

Free (limited messages) · Plus $20/mo · Go ~$8/mo · API

n/a = not published or not yet verified. Scores marked ~ are WhichAI estimates and should not be compared 1:1 with measured scores.

In one line each

Claude Sonnet 5: The strongest free option on the market - frontier-adjacent writing and coding quality at zero cost. Best zero-budget daily driver for text work.

GPT-5.5: The April 2026 flagship, still the strongest broad generalist most people can use free: brainstorming, drafting, frontier coding (SWE-bench Verified 88.7%).

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