Model comparison
GPT-5 Pro vs Grok 4.3
GPT-5 Pro is the stronger model overall, scoring 46.2 to 43.6 on the Noometry Index. Grok 4.3 costs 26× less per token, which makes it the better buy when GPT-5 Pro's lead doesn't matter for your workload.
Last verified . 4 shared benchmarks.
Summary
- They share 4 benchmarks with published results for both. GPT-5 Pro scores higher in 4 categories and Grok 4.3 in 0 categories; 4 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where GPT-5 Pro leads 39.2 to 34.9.
- The biggest single-benchmark swing is FrontierMath (Tiers 1-3): 55.8% for GPT-5 Pro and 42.8% for Grok 4.3.
- Grok 4.3 is cheaper at $1.25 / $2.50 per million input/output tokens, against $15 / $120 for GPT-5 Pro.
- Grok 4.3 accepts more context: 1M tokens versus 400K.
Side by side
| GPT-5 Pro | Grok 4.3 | |
|---|---|---|
| Provider | OpenAI | xAI |
| Noometry Index | 46.2 | 43.6 |
| Released | 2025-10-06 | 2026-04-17 |
| Weights | Proprietary | Proprietary |
| Context window | 400K | 1M |
| Max output | 272K | 30K |
| Input $ / M tokens | $15 | $1.25 |
| Output $ / M tokens | $120 | $2.50 |
| Results tracked | 12 | 40 |
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Category by category
Coding GPT-5 Pro leads
GPT-5 Pro: 43.4 (#77), Grok 4.3: 41.3 (#117)
| Benchmark | GPT-5 Pro | Grok 4.3 |
|---|---|---|
| WeirdML | 60.4% | 49.9% |
| LMArena WebDev | — | 1357 |
| SciCode | — | 47.3% |
| LMArena Coding | — | 1415 |
| ALE-Bench | — | 944.17 |
| AlgoTune | 1.31 | — |
Agentic & Tool Use Not comparable
GPT-5 Pro: —, Grok 4.3: 27.6 (#93)
| Benchmark | GPT-5 Pro | Grok 4.3 |
|---|---|---|
| GDP.pdf | — | 8% |
| LMArena Search | — | 1165 |
| Vending-Bench 2 | — | 35.26 |
Reasoning GPT-5 Pro leads
GPT-5 Pro: 39.2 (#52), Grok 4.3: 34.9 (#60)
| Benchmark | GPT-5 Pro | Grok 4.3 |
|---|---|---|
| Epoch Capabilities Index | 150.26 | 149.13 |
| ARC-AGI-2 | 18.3% | — |
| SimpleBench | 61.6% | — |
| Kagi LLM Benchmark | 76.8% | — |
| NYT Connections (extended) | — | 55.2% |
| ARC-AGI-1 | 70.2% | — |
| CritPt | — | 8% |
| Chess Puzzles | — | 25% |
| EnigmaEval | 18.8% | — |
| LMArena Hard Prompts | — | 1397 |
| DTBench | — | 90.7% |
| LMCA | — | 38.3% |
| ForecastBench | — | 60.3 |
Math GPT-5 Pro leads
GPT-5 Pro: 48.0 (#53), Grok 4.3: 45.8 (#60)
| Benchmark | GPT-5 Pro | Grok 4.3 |
|---|---|---|
| FrontierMath (Tiers 1-3) | 55.8% | 42.8% |
| FrontierMath Tier 4 | 19.5% | 14.6% |
| OTIS Mock AIME 2024-2025 | — | 93.3% |
| ProofBench | — | 11% |
| LMArena Math | — | 1388 |
| FrontierMath Tier 4 (v1) | 14.6% | — |
Knowledge GPT-5 Pro leads
GPT-5 Pro: 56.2 (#39), Grok 4.3: 52.5 (#57)
| Benchmark | GPT-5 Pro | Grok 4.3 |
|---|---|---|
| GPQA Diamond | — | 88.8% |
| Humanity's Last Exam | 31.6% | — |
| SimpleQA Verified | — | 33.2% |
| LMArena Expert | — | 1385 |
Multimodal Not comparable
GPT-5 Pro: —, Grok 4.3: 31.6 (#96)
| Benchmark | GPT-5 Pro | Grok 4.3 |
|---|---|---|
| LMArena Vision | — | 1231 |
| Blueprint-Bench 2 | — | 0% |
Multilingual Not comparable
GPT-5 Pro: —, Grok 4.3: 50.7 (#114)
| Benchmark | GPT-5 Pro | Grok 4.3 |
|---|---|---|
| LMArena Non-English | — | 1385 |
| LMArena Chinese | — | 1423 |
| LMArena French | — | 1412 |
| LMArena German | — | 1395 |
| LMArena Japanese | — | 1379 |
| LMArena Korean | — | 1357 |
| LMArena Russian | — | 1399 |
| LMArena Spanish | — | 1402 |
Instruction Following Not comparable
GPT-5 Pro: —, Grok 4.3: 72.3 (#135)
| Benchmark | GPT-5 Pro | Grok 4.3 |
|---|---|---|
| LMArena Instruction Following | — | 1366 |
Long Context Not comparable
GPT-5 Pro: —, Grok 4.3: 42.5 (#118)
| Benchmark | GPT-5 Pro | Grok 4.3 |
|---|---|---|
| LMArena Longer Query | — | 1393 |
Writing & Preference Not comparable
GPT-5 Pro: —, Grok 4.3: 58.6 (#112)
| Benchmark | GPT-5 Pro | Grok 4.3 |
|---|---|---|
| LMArena Text | — | 1397 |
| LMArena Creative Writing | — | 1380 |
| EQ-Bench 4 | — | 1075 |
| LMArena Multi-Turn | — | 1406 |
Frequently asked questions
Is GPT-5 Pro better than Grok 4.3?
GPT-5 Pro is the stronger model overall, scoring 46.2 to 43.6 on the Noometry Index. Grok 4.3 costs 26× less per token, which makes it the better buy when GPT-5 Pro's lead doesn't matter for your workload.
Which is cheaper, GPT-5 Pro 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; GPT-5 Pro lists at $15 and $120.
Is GPT-5 Pro or Grok 4.3 better for coding?
GPT-5 Pro scores higher on coding benchmarks: 43.4 versus 41.3 in the Noometry coding category.
Which has the bigger context window?
Grok 4.3 does, with 1M tokens against 400K.
How many benchmarks do GPT-5 Pro and Grok 4.3 share?
4 benchmarks have published results for both models. GPT-5 Pro has 12 scored results on Noometry and Grok 4.3 has 40.