Model Comparison
GPT-5.6 Sol vs GPT-5.5 ProWhich is better in 2026?
GPT-5.6 Sol significantly outperforms across most benchmarks. GPT-5.6 Sol is 6.0x cheaper per token.
Verdict: GPT-5.6 Sol vs GPT-5.5 Pro — which is better?
GPT-5.6 Sol (by OpenAI) and GPT-5.5 Pro (by OpenAI) are two of the AI models people compare most. Here is how they stack up on benchmarks, price and capabilities, and which one to pick in 2026.
GPT-5.6 Sol outperforms in 2 benchmarks (BrowseComp, FrontierMath), while GPT-5.5 Pro is better at 0 benchmarks. GPT-5.6 Sol significantly outperforms across most benchmarks.
On price, GPT-5.6 Sol is roughly 6.0x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
Choose GPT-5.6 Sol if…
- you want the strongest raw capability — it leads on 2 of 2 shared benchmarks
- cost matters — it's about 6.0x cheaper per token
- you want the most recent training data — it shipped Jul 2026
Choose GPT-5.5 Pro if…
- you want predictable pricing at $30.00/M input and $180.00/M output
Performance Benchmarks
Comparative analysis across standard metrics
GPT-5.6 Sol outperforms in 2 benchmarks (BrowseComp, FrontierMath), while GPT-5.5 Pro is better at 0 benchmarks.
GPT-5.6 Sol significantly outperforms across most benchmarks.
Arena Performance
Human preference votes
Pricing Analysis
Price comparison per million tokens
For input processing, GPT-5.6 Sol ($5.00/1M tokens) is 6.0x cheaper than GPT-5.5 Pro ($30.00/1M tokens).
For output processing, GPT-5.6 Sol ($30.00/1M tokens) is 6.0x cheaper than GPT-5.5 Pro ($180.00/1M tokens).
In conclusion, GPT-5.5 Pro is more expensive than GPT-5.6 Sol.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
Both models have the same input context window of 1,050,000 tokens. Both models can generate responses up to 128,000 tokens.
Input Capabilities
Supported data types and modalities
Both GPT-5.6 Sol and GPT-5.5 Pro support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
GPT-5.6 Sol
GPT-5.5 Pro
License
Usage and distribution terms
Both models are licensed under proprietary licenses.
Both models have usage restrictions defined by their respective organizations.
Proprietary
Closed source
Proprietary
Closed source
Release Timeline
When each model was launched
GPT-5.6 Sol was released on 2026-07-09, while GPT-5.5 Pro was released on 2026-04-23.
GPT-5.6 Sol is 3 months newer than GPT-5.5 Pro.
Jul 9, 2026
1 weeks ago
2mo newerApr 23, 2026
2 months ago
Knowledge Cutoff
When training data ends
GPT-5.6 Sol has a knowledge cutoff of 2026-02-16, while GPT-5.5 Pro has a cutoff of 2025-12-01.
GPT-5.6 Sol has more recent training data (up to 2026-02-16), making it potentially better informed about events through that date compared to GPT-5.5 Pro (2025-12-01).
Feb 2026
2 mo newerDec 2025
Provider Availability
GPT-5.6 Sol is available from OpenAI. GPT-5.5 Pro is available from OpenAI.
GPT-5.6 Sol
GPT-5.5 Pro
Outputs Comparison
Key Takeaways
GPT-5.6 Sol
View detailsOpenAI
GPT-5.5 Pro
View detailsOpenAI
No standout differentiators in the data we have for this pair.
Detailed Comparison
Interactive Arena
Judge for yourself.
Run your own prompts against GPT-5.6 Sol and GPT-5.5 Pro side-by-side, then vote on the output you prefer.
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FAQ
Common questions about GPT-5.6 Sol vs GPT-5.5 Pro.