Anthropic: Claude Sonnet 5 vs SpaceXAI: Grok 4.3
Side-by-side comparison of specs, pricing, benchmark scores, and task rankings. Updated 2026-11-07.
| Anthropic: Claude Sonnet 5 | SpaceXAI: Grok 4.3 | |
|---|---|---|
| Vendor | anthropic | x-ai |
| Quality Score | 100 | 100 |
| Benchmark Score | 91.4 | 58.6 |
| Input Price | $2.00/M | $1.25/M |
| Output Price | $10.00/M | $2.50/M |
| Context Window | 1,000,000 | 1,000,000 |
| Max Output | 128,000 | 900,000 |
| Tool Calling | ✓ | ✓ |
| Structured Output | ✓ | ✓ |
| Reasoning Mode | ✓ | ✓ |
| Vision | ✓ | ✓ |
| Audio | - | - |
| Benchmark Scores | ||
| ai_index | 88.0 | 62.0 |
| ai_index_agentic | 77.0 | 39.8 |
| ai_index_coding | 100.0 | 69.7 |
The verdict
For a sample job of 1 million input tokens and 250,000 output tokens, Grok 4.3 costs $1.88 and Claude Sonnet 5 costs $4.50, so Grok 4.3 is about 2.4 times cheaper for the same work.
Both read up to 1,000,000 tokens at once, roughly 1,500 pages of text.
On our blended benchmark score Claude Sonnet 5 leads 91.4 to 58.6.
Across the 20 tasks where they differ, Claude Sonnet 5 scores higher on 18 (SQL Generation, Code Review, Code Refactoring and others), Grok 4.3 on 2 (Code Completion, Bulk Data Labeling).
Claude Sonnet 5 was released in June 2026 and Grok 4.3 in April 2026.
Pick Claude Sonnet 5 if you need benchmark performance or the stronger all-round task scores; pick Grok 4.3 if you need lower cost.
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 | Anthropic: Claude Sonnet 5 | SpaceXAI: Grok 4.3 |
|---|---|---|
| SQL Generation | 171 | 158 |
| Code Review | 167 | 155 |
| Code Completion | 119 | 120 |
| Code Refactoring | 164 | 155 |
| Bug Fixing | 180 | 164 |
| Unit Test Generation | 154 | 144 |
| Code Documentation | 141 | 139 |
| Regex Writing | 135 | 130 |
| CI/CD Pipelines | 144 | 136 |
| Frontend Component Design | 146 | 138 |
| Data Analysis | 171 | 153 |
| CSV / Spreadsheet Cleanup | 153 | 147 |
| ETL Scripting | 154 | 145 |
| JSON Extraction | 138 | 134 |
| Bulk Data Labeling | 124 | 124 |
| OCR / Document Parsing | 146 | 141 |
| Table Extraction from PDFs | 146 | 141 |
| Long-Document Summarization | 159 | 152 |
| Short-Form Summarization | 122 | 120 |
| Blog Post Writing | 140 | 134 |
Scores reflect capability match + benchmark data + pricing for each task. Methodology →