GPT-5.5 vs GPT-5.6 Luna Pro
| Signal | GPT-5.5 | Delta | GPT-5.6 Luna Pro |
|---|---|---|---|
Capabilities | 100 | -- | |
Benchmarks | 93 | +5 | |
Pricing | 70 | -24 | |
Context window size | 96 | -- | |
Recency | 100 | -- | |
Output Capacity | 85 | -- | |
| Overall Result | 1 wins | of 6 | 1 wins |
Score History
92.7
current score
GPT-5.5
right now
89
current score
GPT-5.5
OpenAI
GPT-5.6 Luna Pro
OpenAI
GPT-5.6 Luna Pro saves you $1600.00/month
That's $19200.00/year compared to GPT-5.5 at your current usage level of 100K calls/month.
| Metric | GPT-5.5 | GPT-5.6 Luna Pro | Winner |
|---|---|---|---|
| Overall Score | 93 | 89 | GPT-5.5 |
| Rank | #9 | #21 | GPT-5.5 |
| Quality Rank | #9 | #21 | GPT-5.5 |
| Adoption Rank | #9 | #21 | GPT-5.5 |
| Parameters | -- | -- | -- |
| Context Window | 1050K | 1050K | -- |
| Pricing | $5.00/$30.00/M | $1.00/$6.00/M | -- |
| Signal Scores | |||
| Capabilities | 100 | 100 | GPT-5.5 |
| Benchmarks | 93 | 88 | GPT-5.5 |
| Pricing | 70 | 94 | GPT-5.6 Luna Pro |
| Context window size | 96 | 96 | GPT-5.5 |
| Recency | 100 | 100 | GPT-5.5 |
| Output Capacity | 85 | 85 | GPT-5.5 |
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 93/100 (rank #9), placing it in the top 97% of all 290 models tracked.
Scores 89/100 (rank #21), placing it in the top 93% of all 290 models tracked.
With only a 4-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-5.5 when you need:
- Step-by-step reasoning and chain-of-thought problem solving
Choose GPT-5.6 Luna Pro when you need:
- High-volume production workloads where API costs must be minimized
- Step-by-step reasoning and chain-of-thought problem solving
GPT-5.6 Luna Pro offers 80% better value per quality point. At 1M tokens/day, you'd spend $105.00/month with GPT-5.6 Luna Pro vs $525.00/month with GPT-5.5 - a $420.00 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. GPT-5.6 Luna Pro 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 ($6.00/M) reduces costs when processing thousands of records daily
Creative writing & content
Higher overall composite score (93/100) 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-5.5 has a moderate advantage with a 3.700000000000003-point lead in composite score. It wins on more signal dimensions, but GPT-5.6 Luna Pro has specific strengths that could make it the better choice for certain workflows.
By Use Case
Best for Quality
GPT-5.5
Marginally better benchmark scores; both are excellent
Best for Cost
GPT-5.6 Luna Pro
80% lower pricing; better value at scale
Best for Reliability
GPT-5.5
Higher uptime and faster response speeds
Best for Prototyping
GPT-5.5
Stronger community support and better developer experience
Best for Production
GPT-5.5
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-5.5 | GPT-5.6 Luna Pro |
|---|---|---|
| Vision (Image Input) | ||
| Function Calling | ||
| Streaming | ||
| JSON Mode | ||
| Reasoning | ||
| Web Search | ||
| Image Output |
GPT-5.5
OpenAI
GPT-5.6 Luna Pro
OpenAI
GPT-5.6 Luna Pro saves you $36.00/month
That's 80% cheaper than GPT-5.5 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-5.5 | GPT-5.6 Luna Pro |
|---|---|---|
| Context Window | 1.1M | 1.1M |
| Max Output Tokens | 128,000 | 128,000 |
| Open Source | No | No |
| Created | Apr 24, 2026 | Jul 9, 2026 |