GPT-6 Luna vs Mercury 3
GPT-6 Luna leads the LLM Stats Score 43.1 to 36.1. Mercury 3 is 1.2x cheaper per token.
OpenAI · Inception · Updated for 2026
Which is better?
GPT-6 Luna leads the overall LLM Stats Score 43.1 to 36.1, ranking #55 overall.
On price, Mercury 3 is roughly 1.2x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
GPT-6 Luna also accepts a larger context window (1,050,000 input tokens), making it the stronger choice for long documents and large codebases.
Based on current LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.
Choose GPT-6 Luna
- overall performance matters — it scores 43.1 and ranks #55 on LLM Stats
- your work emphasizes agents — it leads those capability indexes
- you process long inputs — it offers a 1,050,000 token context window
Choose Mercury 3
- cost matters — it's about 1.2x cheaper per token
- you want the most recent training data — it shipped Oct 2026
At a glance
The differences that matter most.
Individual benchmarks
5 reported for GPT-6 Luna · 12 for Mercury 3
GPT-6 Luna and Mercury 3don't have any common benchmark datasets to compare. They may have been evaluated on different testing suites.
Human preference
Blind head-to-head votes and playground preference scores
Pricing Analysis
Price comparison per million tokens
For input processing, GPT-6 Luna ($0.10/1M tokens) costs the same as Mercury 3 ($0.10/1M tokens).
For output processing, GPT-6 Luna ($0.50/1M tokens) is 1.4x more expensive than Mercury 3 ($0.35/1M tokens).
In conclusion, GPT-6 Luna is more expensive than Mercury 3.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
GPT-6 Luna accepts 1,050,000 input tokens compared to Mercury 3's 1,000,000 tokens. Mercury 3 can generate longer responses up to 131,072 tokens, while GPT-6 Luna is limited to 128,000 tokens.
Input capabilities
Documented input modalities across available providers
GPT-6 Luna supports multimodal inputs, whereas Mercury 3 does not.
GPT-6 Luna can handle both text and other forms of data like images, making it suitable for multimodal applications.
GPT-6 Luna
Mercury 3
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-6 Luna was released on 2026-09-22, while Mercury 3 was released on 2026-10-19.
Mercury 3 is 1 month newer than GPT-6 Luna.
Sep 22, 2026
3 weeks ago
Oct 19, 2026
0 days ago
3w newerKnowledge Cutoff
When training data ends
GPT-6 Luna has a documented knowledge cutoff of 2026-05-18, while Mercury 3's cutoff date is not specified.
We can confirm GPT-6 Luna's training data extends to 2026-05-18, but cannot make a direct comparison without Mercury 3's cutoff date.
May 2026
—
Provider Availability
GPT-6 Luna is available from OpenAI. Mercury 3 is available from Inception.
GPT-6 Luna
Mercury 3
Outputs Comparison
Judge for yourself.
Run your own prompts against GPT-6 Luna and Mercury 3 side-by-side, then vote on the output you prefer.
FAQ
Common questions about GPT-6 Luna vs Mercury 3.