Model comparison
Claude Opus 5 vs Grok 4.3
Claude Opus 5 is the stronger model overall, scoring 67.7 to 43.6 on the Noometry Index. Grok 4.3 costs 6.4× less per token, which makes it the better buy when Claude Opus 5's lead doesn't matter for your workload.
Last verified . 38 shared benchmarks.
Summary
- They share 38 benchmarks with published results for both. Claude Opus 5 scores higher in 10 categories and Grok 4.3 in 0 categories; 10 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where Claude Opus 5 leads 77.1 to 34.9.
- The biggest single-benchmark swing is ProofBench: 99% for Claude Opus 5 and 11% for Grok 4.3.
- Grok 4.3 is cheaper at $1.25 / $2.50 per million input/output tokens, against $5 / $25 for Claude Opus 5.
Side by side
| Claude Opus 5 | Grok 4.3 | |
|---|---|---|
| Provider | Anthropic | xAI |
| Noometry Index | 67.7 | 43.6 |
| Released | 2026-07-24 | 2026-04-17 |
| Weights | Proprietary | Proprietary |
| Context window | 1M | 1M |
| Max output | 128K | 30K |
| Input $ / M tokens | $5 | $1.25 |
| Output $ / M tokens | $25 | $2.50 |
| Results tracked | 57 | 40 |
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Category by category
Coding Claude Opus 5 leads
Claude Opus 5: 67.0 (#5), Grok 4.3: 41.3 (#117)
| Benchmark | Claude Opus 5 | Grok 4.3 |
|---|---|---|
| LMArena WebDev | 1694 | 1357 |
| SciCode | 56.4% | 47.3% |
| WeirdML | 91.8% | 49.9% |
| LMArena Coding | 1533 | 1415 |
| ALE-Bench | 2,165 | 944.17 |
| DeepSWE | 73.6% | — |
| FrontierCode | 53.4% | — |
| CursorBench | 46.6% | — |
| FrontierSWE | 52% | — |
Agentic & Tool Use Claude Opus 5 leads
Claude Opus 5: 55.5 (#1), Grok 4.3: 27.6 (#93)
| Benchmark | Claude Opus 5 | Grok 4.3 |
|---|---|---|
| GDP.pdf | 24% | 8% |
| Vending-Bench 2 | 11,182 | 35.26 |
| APEX-Agents | 65.8% | — |
| OSWorld 2.0 | 31.4% | — |
| τ²-bench Banking | 48.7% | — |
| PostTrainBench | 35% | — |
| BALROG | 63.4% | — |
| GBAEval | 79.6% | — |
| LMArena Search | — | 1165 |
Reasoning Claude Opus 5 leads
Claude Opus 5: 77.1 (#3), Grok 4.3: 34.9 (#60)
| Benchmark | Claude Opus 5 | Grok 4.3 |
|---|---|---|
| NYT Connections (extended) | 94.3% | 55.2% |
| CritPt | 29.1% | 8% |
| Chess Puzzles | 42% | 25% |
| LMArena Hard Prompts | 1525 | 1397 |
| DTBench | 97.9% | 90.7% |
| LMCA | 64.5% | 38.3% |
| Epoch Capabilities Index | 162.67 | 149.13 |
| ARC-AGI-2 | 90.4% | — |
| SimpleBench | 80.6% | — |
| ARC-AGI-1 | 97.5% | — |
| EBR-Bench | 45.7% | — |
| Mystery Game Puzzles | 59% | — |
| Bench to the Future 3 | 0.12 | — |
| ForecastBench | — | 60.3 |
Math Claude Opus 5 leads
Claude Opus 5: 86.1 (#6), Grok 4.3: 45.8 (#60)
| Benchmark | Claude Opus 5 | Grok 4.3 |
|---|---|---|
| FrontierMath (Tiers 1-3) | 85.6% | 42.8% |
| FrontierMath Tier 4 | 73.2% | 14.6% |
| OTIS Mock AIME 2024-2025 | 98.9% | 93.3% |
| ProofBench | 99% | 11% |
| LMArena Math | 1533 | 1388 |
Knowledge Claude Opus 5 leads
Claude Opus 5: 66.8 (#8), Grok 4.3: 52.5 (#57)
| Benchmark | Claude Opus 5 | Grok 4.3 |
|---|---|---|
| GPQA Diamond | 93.9% | 88.8% |
| SimpleQA Verified | 59.9% | 33.2% |
| LMArena Expert | 1558 | 1385 |
Multimodal Claude Opus 5 leads
Claude Opus 5: 51.1 (#6), Grok 4.3: 31.6 (#96)
| Benchmark | Claude Opus 5 | Grok 4.3 |
|---|---|---|
| LMArena Vision | 1321 | 1231 |
| Blueprint-Bench 2 | 30.4% | 0% |
| Furniture Assembly | 60.8% | — |
| LMArena Document | 1516 | — |
Multilingual Claude Opus 5 leads
Claude Opus 5: 58.8 (#3), Grok 4.3: 50.7 (#114)
| Benchmark | Claude Opus 5 | Grok 4.3 |
|---|---|---|
| LMArena Non-English | 1500 | 1385 |
| LMArena Chinese | 1575 | 1423 |
| LMArena French | 1522 | 1412 |
| LMArena German | 1522 | 1395 |
| LMArena Japanese | 1510 | 1379 |
| LMArena Korean | 1526 | 1357 |
| LMArena Russian | 1507 | 1399 |
| LMArena Spanish | 1519 | 1402 |
Instruction Following Claude Opus 5 leads
Claude Opus 5: 79.3 (#5), Grok 4.3: 72.3 (#135)
| Benchmark | Claude Opus 5 | Grok 4.3 |
|---|---|---|
| LMArena Instruction Following | 1516 | 1366 |
Long Context Claude Opus 5 leads
Claude Opus 5: 46.5 (#20), Grok 4.3: 42.5 (#118)
| Benchmark | Claude Opus 5 | Grok 4.3 |
|---|---|---|
| LMArena Longer Query | 1516 | 1393 |
Writing & Preference Claude Opus 5 leads
Claude Opus 5: 79.3 (#2), Grok 4.3: 58.6 (#112)
| Benchmark | Claude Opus 5 | Grok 4.3 |
|---|---|---|
| LMArena Text | 1506 | 1397 |
| LMArena Creative Writing | 1491 | 1380 |
| EQ-Bench 4 | 1385 | 1075 |
| LMArena Multi-Turn | 1496 | 1406 |
| EQ-Bench Creative Writing | 2133 | — |
Frequently asked questions
Is Claude Opus 5 better than Grok 4.3?
Claude Opus 5 is the stronger model overall, scoring 67.7 to 43.6 on the Noometry Index. Grok 4.3 costs 6.4× less per token, which makes it the better buy when Claude Opus 5's lead doesn't matter for your workload.
Which is cheaper, Claude Opus 5 or Grok 4.3?
Grok 4.3 is cheaper. It lists at $1.25 per million input tokens and $2.50 per million output tokens; Claude Opus 5 lists at $5 and $25.
Is Claude Opus 5 or Grok 4.3 better for coding?
Claude Opus 5 scores higher on coding benchmarks: 67.0 versus 41.3 in the Noometry coding category.
Which has the bigger context window?
Both accept 1M tokens.
How many benchmarks do Claude Opus 5 and Grok 4.3 share?
38 benchmarks have published results for both models. Claude Opus 5 has 57 scored results on Noometry and Grok 4.3 has 40.