GPT-6 Luna Pro vs Mercury 3
| Signal | GPT-6 Luna Pro | Delta | Mercury 3 |
|---|---|---|---|
Capabilities | 100 | +33 | |
Pricing | 100 | 0 | |
Context window size | 96 | +0 | |
Recency | 100 | -- | |
Output Capacity | 82 | 0 | |
| Overall Result | 2 wins | of 5 | 2 wins |
Score History
40
current score
Tied
right now
40
current score
GPT-6 Luna Pro
OpenAI
Mercury 3
Inception
Mercury 3 saves you $7.50/month
That's $90.00/year compared to GPT-6 Luna Pro at your current usage level of 100K calls/month.
| Metric | GPT-6 Luna Pro | Mercury 3 | Winner |
|---|---|---|---|
| Overall Score | 40 | 40 | -- |
| Rank | #220 | #191 | Mercury 3 |
| Quality Rank | #220 | #191 | Mercury 3 |
| Adoption Rank | #220 | #191 | Mercury 3 |
| Parameters | -- | -- | -- |
| Context Window | 1050K | 1000K | GPT-6 Luna Pro |
| Pricing | $0.10/$0.50/M | $0.10/$0.35/M | -- |
| Signal Scores | |||
| Capabilities | 100 | 67 | GPT-6 Luna Pro |
| Pricing | 100 | 100 | Mercury 3 |
| Context window size | 96 | 95 | GPT-6 Luna Pro |
| Recency | 100 | 100 | GPT-6 Luna Pro |
| Output Capacity | 82 | 82 | Mercury 3 |
Our score (0-100) is driven by benchmark performance (90%) from Arena Elo ratings, MMLU, GPQA, HumanEval, SWE-bench, and 15+ standardized evaluations. Capabilities and context window serve as tiebreakers (10%). Learn more about our methodology.
Scores 40/100 (rank #220), placing it in the top 24% of all 290 models tracked.
Scores 40/100 (rank #191), placing it in the top 34% of all 290 models tracked.
With only a 0-point gap, these models are in the same performance tier. The practical difference in output quality is minimal - your choice should depend on pricing, latency requirements, and specific feature needs.
Choose GPT-6 Luna Pro when you need:
- Multimodal workflows that require image understanding
- Step-by-step reasoning and chain-of-thought problem solving
Choose Mercury 3 when you need:
- Step-by-step reasoning and chain-of-thought problem solving
Mercury 3 offers 25% better value per quality point. At 1M tokens/day, you'd spend $6.75/month with Mercury 3 vs $9.00/month with GPT-6 Luna Pro - a $2.25 monthly difference.
Both models have comparable response speeds. For most applications, the latency difference is negligible.
When latency matters most: Interactive chatbots, IDE code completion, real-time translation, and user-facing applications where response time directly impacts experience. For batch processing, background summarization, or offline analysis, latency is less critical.
Code generation & review
Based on overall model capabilities and architecture for coding tasks like generating functions, debugging, and refactoring
Customer support chatbot
Suitable for user-facing chat with competitive response times. Mercury 3 also offers lower per-token costs for high-volume support
Long document analysis
Larger context window (1050K tokens) can process longer documents, contracts, and research papers in a single pass
Batch data extraction
Lower output pricing ($0.35/M) reduces costs when processing thousands of records daily
Creative writing & content
Higher overall composite score (40/100) correlates with better nuance, coherence, and style in long-form content
Image understanding & OCR
Supports vision input - can analyze screenshots, diagrams, photos, and scanned documents directly
GPT-6 Luna Pro and Mercury 3 are extremely close in overall performance (only 0 points apart). Your best choice depends entirely on which specific strengths matter most for your use case.
By Use Case
Best for Quality
GPT-6 Luna Pro
Marginally better benchmark scores; both are excellent
Best for Cost
Mercury 3
25% lower pricing; better value at scale
Best for Reliability
GPT-6 Luna Pro
Higher uptime and faster response speeds
Best for Prototyping
GPT-6 Luna Pro
Stronger community support and better developer experience
Best for Production
GPT-6 Luna Pro
Wider enterprise adoption and proven at scale
by OpenAI
- Choose for Quality - Marginally better benchmark scores; both are excellent
- Choose for Reliability - Higher uptime and faster response speeds
- Choose for Prototyping - Stronger community support and better developer experience
- Choose for Production - Wider enterprise adoption and proven at scale
| Capability | GPT-6 Luna Pro | Mercury 3 |
|---|---|---|
| Vision (Image Input)differs | ||
| Function Calling | ||
| Streaming | ||
| JSON Mode | ||
| Reasoning | ||
| Web Searchdiffers | ||
| Image Output |
GPT-6 Luna Pro
OpenAI
Mercury 3
Inception
Mercury 3 saves you $0.1800/month
That's 23% cheaper than GPT-6 Luna Pro at 1,000 tokens/request and 100 requests/day.
Assumes 60% input / 40% output token ratio per request. Actual costs may vary based on your usage pattern.
| Parameter | GPT-6 Luna Pro | Mercury 3 |
|---|---|---|
| Context Window | 1.1M | 1M |
| Max Output Tokens | 128,000 | 131,072 |
| Open Source | No | No |
| Created | Sep 22, 2026 | Oct 16, 2026 |