Model Comparison
GPT-5.4 vs GPT-5.6 LunaWhich is better in 2026?
GPT-5.6 Luna shows notably better performance in the majority of benchmarks. GPT-5.6 Luna is 2.5x cheaper per token.
Verdict: GPT-5.4 vs GPT-5.6 Luna — which is better?
GPT-5.4 (by OpenAI) and GPT-5.6 Luna (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-5.4 outperforms in 3 benchmarks (GPQA, MMMU-Pro, Toolathlon), while GPT-5.6 Luna is better at 5 benchmarks (BrowseComp, FrontierMath, GDPval-AA, Graphwalks BFS >128k, SWE-Bench Pro). GPT-5.6 Luna shows notably better performance in the majority of benchmarks.
On price, GPT-5.6 Luna is roughly 2.5x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
GPT-5.6 Luna also accepts a larger context window (1,050,000 input tokens), making it the stronger choice for long documents and large codebases.
Choose GPT-5.4 if…
- you want predictable pricing at $2.50/M input and $15.00/M output
Choose GPT-5.6 Luna if…
- you want the strongest raw capability — it leads on 5 of 8 shared benchmarks
- cost matters — it's about 2.5x cheaper per token
- you process long inputs — it offers a 1,050,000 token context window
- you want the most recent training data — it shipped Jul 2026
Performance Benchmarks
Comparative analysis across standard metrics
GPT-5.4 outperforms in 3 benchmarks (GPQA, MMMU-Pro, Toolathlon), while GPT-5.6 Luna is better at 5 benchmarks (BrowseComp, FrontierMath, GDPval-AA, Graphwalks BFS >128k, SWE-Bench Pro).
GPT-5.6 Luna shows notably better performance in the majority of benchmarks.
Arena Performance
Human preference votes
Pricing Analysis
Price comparison per million tokens
For input processing, GPT-5.4 ($2.50/1M tokens) is 2.5x more expensive than GPT-5.6 Luna ($1.00/1M tokens).
For output processing, GPT-5.4 ($15.00/1M tokens) is 2.5x more expensive than GPT-5.6 Luna ($6.00/1M tokens).
In conclusion, GPT-5.4 is more expensive than GPT-5.6 Luna.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
GPT-5.6 Luna accepts 1,050,000 input tokens compared to GPT-5.4's 1,000,000 tokens. Both models can generate responses up to 128,000 tokens.
Input Capabilities
Supported data types and modalities
Both GPT-5.4 and GPT-5.6 Luna support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
GPT-5.4
GPT-5.6 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-5.4 was released on 2026-03-05, while GPT-5.6 Luna was released on 2026-07-09.
GPT-5.6 Luna is 4 months newer than GPT-5.4.
Mar 5, 2026
4 months ago
Jul 9, 2026
1 weeks ago
4mo newerKnowledge Cutoff
When training data ends
GPT-5.6 Luna has a documented knowledge cutoff of 2026-02-16, while GPT-5.4's cutoff date is not specified.
We can confirm GPT-5.6 Luna's training data extends to 2026-02-16, but cannot make a direct comparison without GPT-5.4's cutoff date.
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Feb 2026
Provider Availability
GPT-5.4 is available from OpenAI. GPT-5.6 Luna is available from OpenAI.
GPT-5.4
GPT-5.6 Luna
Outputs Comparison
Key Takeaways
GPT-5.4
View detailsOpenAI
GPT-5.6 Luna
View detailsOpenAI
Detailed Comparison
Interactive Arena
Judge for yourself.
Run your own prompts against GPT-5.4 and GPT-5.6 Luna side-by-side, then vote on the output you prefer.
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FAQ
Common questions about GPT-5.4 vs GPT-5.6 Luna.