GPT-5.6 Sol vs GPT-6 Luna
GPT-5.6 Sol leads the LLM Stats Score 54.4 to 44.5. GPT-6 Luna is 56.3x cheaper per token.
OpenAI · OpenAI · Updated for 2026
Which is better?
GPT-5.6 Sol leads the overall LLM Stats Score 54.4 to 44.5, ranking #5 overall.
In the 4 individual benchmarks reported for both models, GPT-5.6 Sol wins 4; this is a narrower head-to-head signal than the composite indexes.
On price, GPT-6 Luna is roughly 56.3x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
Based on current LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.
Choose GPT-5.6 Sol
- overall performance matters — it scores 54.4 and ranks #5 on LLM Stats
- your work emphasizes reasoning and coding — it leads those capability indexes
- you value its reported benchmark strengths — it wins 4 of 4 exact shared results
Choose GPT-6 Luna
- cost matters — it's about 56.3x cheaper per token
- you want the most recent training data — it shipped Sep 2026
At a glance
The differences that matter most.
Capability indexes
Additional strengths measured across groups of related public benchmarks
Individual benchmarks
45 reported for GPT-5.6 Sol · 5 for GPT-6 Luna
GPT-5.6 Sol outperforms in 4 benchmarks (Agents' Last Exam, DeepSWE 1.1, FrontierCode 1.1, OSWorld 2.0), while GPT-6 Luna is better at 0 benchmarks.
GPT-5.6 Sol significantly outperforms across most benchmarks.
Human preference
Blind head-to-head votes and playground preference scores
Pricing Analysis
Price comparison per million tokens
For input processing, GPT-5.6 Sol ($5.00/1M tokens) is 50.0x more expensive than GPT-6 Luna ($0.10/1M tokens).
For output processing, GPT-5.6 Sol ($30.00/1M tokens) is 60.0x more expensive than GPT-6 Luna ($0.50/1M tokens).
In conclusion, GPT-5.6 Sol is more expensive than GPT-6 Luna.*
* 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
Documented input modalities across available providers
Both GPT-5.6 Sol and GPT-6 Luna support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
GPT-5.6 Sol
GPT-6 Luna
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-6 Luna was released on 2026-09-22.
GPT-6 Luna is 3 months newer than GPT-5.6 Sol.
Jul 9, 2026
2 months ago
Sep 22, 2026
0 days ago
2mo newerKnowledge Cutoff
When training data ends
GPT-5.6 Sol has a knowledge cutoff of 2026-02-16, while GPT-6 Luna has a cutoff of 2026-05-18.
GPT-6 Luna has more recent training data (up to 2026-05-18), making it potentially better informed about events through that date compared to GPT-5.6 Sol (2026-02-16).
Feb 2026
May 2026
3 mo newerProvider Availability
GPT-5.6 Sol is available from OpenAI. GPT-6 Luna is available from OpenAI.
GPT-5.6 Sol
GPT-6 Luna
Outputs Comparison
Judge for yourself.
Run your own prompts against GPT-5.6 Sol and GPT-6 Luna side-by-side, then vote on the output you prefer.
FAQ
Common questions about GPT-5.6 Sol vs GPT-6 Luna.