OpenAI: GPT-5.6 Luna vs Anthropic: Claude Sonnet 5
Side-by-side comparison of specs, pricing, benchmark scores, and task rankings. Updated 2026-10-09.
| OpenAI: GPT-5.6 Luna | Anthropic: Claude Sonnet 5 | |
|---|---|---|
| Vendor | openai | anthropic |
| Quality Score | 100 | 100 |
| Benchmark Score | 62.3 | 63.9 |
| Input Price | $0.20/M | $2.00/M |
| Output Price | $1.20/M | $10.00/M |
| Context Window | 1,050,000 | 1,000,000 |
| Max Output | 128,000 | 128,000 |
| Tool Calling | ✓ | ✓ |
| Structured Output | ✓ | ✓ |
| Reasoning Mode | ✓ | ✓ |
| Vision | ✓ | ✓ |
| Audio | - | - |
| Benchmark Scores | ||
| ai_index | 61.6 | 63.0 |
The verdict
For a sample job of 1 million input tokens and 250,000 output tokens, GPT-5.6 Luna costs $0.50 and Claude Sonnet 5 costs $4.50, so GPT-5.6 Luna is about 9.0 times cheaper for the same work.
Both take in a similar amount of text: 1,050,000 and 1,000,000 tokens, about 1,575 and 1,500 pages.
On our blended benchmark score Claude Sonnet 5 leads 63.9 to 62.3.
Across the 20 tasks where they differ, GPT-5.6 Luna scores higher on 10 (SQL Generation, Code Completion, Code Documentation and others), Claude Sonnet 5 on 10 (Code Review, Code Refactoring, Bug Fixing and others).
GPT-5.6 Luna was released in July 2026 and Claude Sonnet 5 in June 2026.
Pick GPT-5.6 Luna if you need lower cost; pick Claude Sonnet 5 if you need benchmark performance.
Costs use current list prices per million tokens; page counts assume about 0.75 words per token and 500 words per page.
Who wins by task?
| Task | OpenAI: GPT-5.6 Luna | Anthropic: Claude Sonnet 5 |
|---|---|---|
| SQL Generation | 141 | 140 |
| Code Review | 143 | 144 |
| Code Completion | 133 | 118 |
| Code Refactoring | 145 | 146 |
| Bug Fixing | 147 | 148 |
| Unit Test Generation | 131 | 131 |
| Code Documentation | 137 | 135 |
| Regex Writing | 125 | 123 |
| CI/CD Pipelines | 127 | 127 |
| Frontend Component Design | 129 | 129 |
| Data Analysis | 133 | 133 |
| CSV / Spreadsheet Cleanup | 136 | 135 |
| ETL Scripting | 136 | 136 |
| JSON Extraction | 131 | 121 |
| Bulk Data Labeling | 129 | 118 |
| OCR / Document Parsing | 134 | 134 |
| Table Extraction from PDFs | 134 | 134 |
| Long-Document Summarization | 147 | 146 |
| Short-Form Summarization | 126 | 116 |
| Blog Post Writing | 129 | 128 |
Scores reflect capability match + benchmark data + pricing for each task. Methodology →