Claude Opus 4.8 (Fast) vs GPT-5.6 Luna Pro
| Signal | Claude Opus 4.8 (Fast) | Delta | GPT-5.6 Luna Pro |
|---|---|---|---|
Capabilities | 100 | -- | |
Benchmarks | 93 | +5 | |
Pricing | 50 | -44 | |
Context window size | 86 | 0 | |
Recency | 100 | -- | |
Output Capacity | 85 | -- | |
| Overall Result | 1 wins | of 6 | 2 wins |
Score History
94.7
current score
Claude Opus 4.8 (Fast)
right now
88.5
current score
Claude Opus 4.8 (Fast)
Anthropic
GPT-5.6 Luna Pro
OpenAI
GPT-5.6 Luna Pro saves you $3100.00/month
That's $37200.00/year compared to Claude Opus 4.8 (Fast) at your current usage level of 100K calls/month.
| Metric | Claude Opus 4.8 (Fast) | GPT-5.6 Luna Pro | Winner |
|---|---|---|---|
| Overall Score | 95 | 89 | Claude Opus 4.8 (Fast) |
| Rank | #2 | #19 | Claude Opus 4.8 (Fast) |
| Quality Rank | #2 | #19 | Claude Opus 4.8 (Fast) |
| Adoption Rank | #2 | #19 | Claude Opus 4.8 (Fast) |
| Parameters | -- | -- | -- |
| Context Window | 1000K | 1050K | GPT-5.6 Luna Pro |
| Pricing | $10.00/$50.00/M | $1.00/$6.00/M | -- |
| Signal Scores | |||
| Capabilities | 100 | 100 | Claude Opus 4.8 (Fast) |
| Benchmarks | 93 | 88 | Claude Opus 4.8 (Fast) |
| Pricing | 50 | 94 | GPT-5.6 Luna Pro |
| Context window size | 86 | 86 | GPT-5.6 Luna Pro |
| Recency | 100 | 100 | Claude Opus 4.8 (Fast) |
| Output Capacity | 85 | 85 | Claude Opus 4.8 (Fast) |
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 95/100 (rank #2), placing it in the top 100% of all 290 models tracked.
Scores 89/100 (rank #19), placing it in the top 94% of all 290 models tracked.
Claude Opus 4.8 (Fast) has a 6-point advantage, which typically translates to noticeably better performance on complex reasoning, code generation, and multi-step tasks.
Choose Claude Opus 4.8 (Fast) 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 88% better value per quality point. At 1M tokens/day, you'd spend $105.00/month with GPT-5.6 Luna Pro vs $900.00/month with Claude Opus 4.8 (Fast) - a $795.00 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 (95/100) 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
Claude Opus 4.8 (Fast) has a moderate advantage with a 6.200000000000003-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
Claude Opus 4.8 (Fast)
Marginally better benchmark scores; both are excellent
Best for Cost
GPT-5.6 Luna Pro
88% lower pricing; better value at scale
Best for Reliability
Claude Opus 4.8 (Fast)
Higher uptime and faster response speeds
Best for Prototyping
Claude Opus 4.8 (Fast)
Stronger community support and better developer experience
Best for Production
Claude Opus 4.8 (Fast)
Wider enterprise adoption and proven at scale
by Anthropic
- 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 | Claude Opus 4.8 (Fast) | GPT-5.6 Luna Pro |
|---|---|---|
| Vision (Image Input) | ||
| Function Calling | ||
| Streaming | ||
| JSON Mode | ||
| Reasoning | ||
| Web Search | ||
| Image Output |
Claude Opus 4.8 (Fast)
Anthropic
GPT-5.6 Luna Pro
OpenAI
GPT-5.6 Luna Pro saves you $69.00/month
That's 88% cheaper than Claude Opus 4.8 (Fast) 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 | Claude Opus 4.8 (Fast) | GPT-5.6 Luna Pro |
|---|---|---|
| Context Window | 1M | 1.1M |
| Max Output Tokens | 128,000 | 128,000 |
| Open Source | No | No |
| Created | May 27, 2026 | Jul 9, 2026 |