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OpenAIGPT-5.5 ProVSOpenAIGPT-5.6 Sol

Analysis by:the whichllmmodel Editorial Team|Updated: June 2026

Our Take

Standardized reasoning and coding benchmarks are currently pending verification for one or both of these models. We recommend testing GPT-5.5 Pro and GPT-5.6 Sol directly in their respective provider playgrounds to see which fits your specific prompt styles best.
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Model Specs

GPT-5.5 Pro

Benchmarks & Scores

Coding (swe-bench-pro)
N/A

excellent at multi-file repositories, autonomous agents, and industrial codebases

Reasoning (gpqa-diamond)Winner (+1.6%)
96.2%

graduate-level science QA

Cost & Context

Cost (per 1M tokens)
$67.50Input: $30.00 | Output: $180.00
Context Window
1.05M tokens
Model Specs

GPT-5.6 Sol

Benchmarks & Scores

Coding (swe-bench-pro)
64.6%

excellent at multi-file repositories, autonomous agents, and industrial codebases

Reasoning (gpqa-diamond)
94.6%

graduate-level science QA

Cost & Context

Cost (per 1M tokens)6.0x cheaper
$11.25Input: $5.00 | Output: $30.00
Context Window
1.05M tokens

Frequently Asked Questions about GPT-5.5 Pro vs GPT-5.6 Sol

GPT-5.6 Sol is cheaper than GPT-5.5 Pro. GPT-5.6 Sol has a blended cost of $11.25/1M tokens, which is about 6.0x cheaper than GPT-5.5 Pro at $67.50/1M tokens.

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