Claude Sonnet 5 vs Grok 4.3
Claude Sonnet 5 
Grok 4.3 Verdict
- Claude Sonnet 5 (high) and Grok 4.3 (medium) are level on quality (61.4 vs 60.7).
- Claude Sonnet 5 (high) is stronger in agents & tools, coding, composite, human preference, long context, multimodal, reasoning.
- Grok 4.3 (medium) is stronger in knowledge, instruction following.
- Grok 4.3 (medium) is 2.6× cheaper ($1.56 vs $4.00 per 1M blended).
- Grok 4.3 (medium) streams 1.9× faster (112 vs 60 tokens per second).
| Metric | Claude Sonnet 5 (high) | Grok 4.3 (medium) |
|---|---|---|
| BenchLeader Index | 61.4 | 60.7 |
| Agents & tools score | 61.8 | 60.1 |
| Coding score | 61.6 | – |
| Composite score | 69.5 | 60.3 |
| Human preference score | 66.2 | – |
| Knowledge score | 62.4 | 72.1 |
| Long context score | 64.8 | 64.0 |
| Multimodal score | 63.1 | 60.2 |
| Reasoning score | 66.8 | – |
| Instruction following score | – | 80.0 |
| Blended price $/M | $4.00 | $1.56 |
| Output speed | 60 tok/s | 112 tok/s |
| Time to first answer | 10.0 s | 12.1 s |
| Context window | 1M | 1M |
| SciCode | 48.6% | – |
| WeirdML | 68.8% | – |
| LMArena Text | 1462 | – |
| LMArena Hard Prompts | 1490 | – |
| LMArena Coding | 1521 | – |
| LMArena WebDev | 1538 | – |
| LMArena Vision | 1278 | – |
| LMArena Agent | 6.3 | – |
| AA Intelligence Index | 32.0 | 24.8 |
| IFBench | – | 83.3% |
| AA-LCR | 76.7% | 75.0% |
| MMMU-Pro | – | 75.8% |
| AA-Omniscience | -3.7 | 16.7 |
| Terminal-Bench Hard | – | 30.3% |
| GPQA Diamond (AA) | – | 89.0% |
| Humanity's Last Exam (AA) | 35.7% | 30.0% |
| SciCode (AA) | 54.3% | – |
| τ²-Bench Telecom (AA) | – | 91.2% |
Data as of 2026-09-10. Best configuration of each model; every score links to its source on the model pages.
Claude Sonnet 5 vs Grok 4.3: questions
- Is Claude Sonnet 5 better than Grok 4.3?
- Claude Sonnet 5 (high) and Grok 4.3 (medium) are level on quality (61.4 vs 60.7). The BenchLeader Index combines every independent quality benchmark; Claude Sonnet 5 (high) is ahead overall as of 2026-09-10, but check the category scores for your use.
- Is Claude Sonnet 5 better than Grok 4.3 for agentic tasks?
- Claude Sonnet 5 scores higher in agentic tasks (62 vs 60 on the category index, where 50 is average).
- Which is cheaper, Claude Sonnet 5 or Grok 4.3?
- Grok 4.3 is cheaper: $1.56 against $4.00 per million tokens, blended at three input tokens per output token.
- Which is faster, Claude Sonnet 5 or Grok 4.3?
- Grok 4.3 streams faster: 112 against 60 output tokens per second.
- Which has the larger context window?
- Both accept 1M tokens of context.