Model comparison
Claude Opus 4.1 vs GPT-5-Codex
Claude Opus 4.1 is the stronger model overall, scoring 41.0 to 37.9 on the Noometry Index. GPT-5-Codex costs 8.7× less per token, which makes it the better buy when Claude Opus 4.1's lead doesn't matter for your workload.
Last verified . 2 shared benchmarks.
Summary
- They share 2 benchmarks with published results for both. Claude Opus 4.1 scores higher in 3 categories and GPT-5-Codex in 0 categories; 3 gaps are clear of the uncertainty.
- The widest gap is in agentic & tool use, where Claude Opus 4.1 leads 35.0 to 31.0.
- The biggest single-benchmark swing is WeirdML: 45.9% for Claude Opus 4.1 and 54.5% for GPT-5-Codex.
- GPT-5-Codex is cheaper at $1.25 / $10 per million input/output tokens, against $15 / $75 for Claude Opus 4.1.
- GPT-5-Codex accepts more context: 400K tokens versus 200K.
Side by side
| Claude Opus 4.1 | GPT-5-Codex | |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Noometry Index | 41.0 | 37.9 |
| Released | 2025-08-05 | 2025-09-15 |
| Weights | Proprietary | Proprietary |
| Context window | 200K | 400K |
| Max output | 32K | 128K |
| Input $ / M tokens | $15 | $1.25 |
| Output $ / M tokens | $75 | $10 |
| Results tracked | 48 | 3 |
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Category by category
Coding Claude Opus 4.1 leads
Claude Opus 4.1: 44.4 (#73), GPT-5-Codex: 42.4 (#103)
| Benchmark | Claude Opus 4.1 | GPT-5-Codex |
|---|---|---|
| WeirdML | 45.9% | 54.5% |
| SWE-bench Verified | 73.3% | — |
| LMArena WebDev | 1390 | — |
| LMArena Coding | 1479 | — |
| ALE-Bench | 674.77 | — |
| AlgoTune | 1.34 | — |
Agentic & Tool Use Claude Opus 4.1 leads
Claude Opus 4.1: 35.0 (#41), GPT-5-Codex: 31.0 (#72)
| Benchmark | Claude Opus 4.1 | GPT-5-Codex |
|---|---|---|
| Terminal-Bench | 38% | 44.3% |
| GDPval | 43.6% | — |
| Cybench | 42% | — |
| DeepResearch Bench | 48.3% | — |
| LMArena Search | 1148 | — |
| METR Time Horizons | 66.8% | — |
Reasoning Claude Opus 4.1 leads
Claude Opus 4.1: 32.2 (#76), GPT-5-Codex: 30.9 (#83)
| Benchmark | Claude Opus 4.1 | GPT-5-Codex |
|---|---|---|
| SimpleBench | 60% | — |
| Kagi LLM Benchmark | — | 70.3% |
| Chess Puzzles | 7% | — |
| EnigmaEval | 7.2% | — |
| EBR-Bench | 7.9% | — |
| LMArena Hard Prompts | 1443 | — |
| Mystery Game Puzzles | 21% | — |
| DTBench | 80% | — |
| LMCA | 37.1% | — |
| Epoch Capabilities Index | 144.12 | — |
| ForecastBench | 62 | — |
Math Not comparable
Claude Opus 4.1: 22.3 (#277), GPT-5-Codex: —
| Benchmark | Claude Opus 4.1 | GPT-5-Codex |
|---|---|---|
| FrontierMath (Tiers 1-3) | 12.6% | — |
| FrontierMath Tier 4 | 2.4% | — |
| OTIS Mock AIME 2024-2025 | 68.9% | — |
| LMArena Math | 1431 | — |
| FrontierMath (Feb 2025 set) | 7.2% | — |
| FrontierMath Tier 4 (v1) | 4.2% | — |
Knowledge Not comparable
Claude Opus 4.1: 42.0 (#101), GPT-5-Codex: —
| Benchmark | Claude Opus 4.1 | GPT-5-Codex |
|---|---|---|
| GPQA Diamond | 77.3% | — |
| Humanity's Last Exam | 11.5% | — |
| Confabulations | 17.1% | — |
| Vectara Hallucination Rate | 11.8% | — |
| LMArena Expert | 1439 | — |
Multimodal Not comparable
Claude Opus 4.1: 26.8 (#119), GPT-5-Codex: —
| Benchmark | Claude Opus 4.1 | GPT-5-Codex |
|---|---|---|
| VPCT | 35% | — |
Multilingual Not comparable
Claude Opus 4.1: 52.0 (#95), GPT-5-Codex: —
| Benchmark | Claude Opus 4.1 | GPT-5-Codex |
|---|---|---|
| LMArena Non-English | 1405 | — |
| LMArena Chinese | 1427 | — |
| LMArena French | 1431 | — |
| LMArena German | 1413 | — |
| LMArena Japanese | 1378 | — |
| LMArena Korean | 1380 | — |
| LMArena Russian | 1422 | — |
| LMArena Spanish | 1448 | — |
Instruction Following Not comparable
Claude Opus 4.1: 75.6 (#58), GPT-5-Codex: —
| Benchmark | Claude Opus 4.1 | GPT-5-Codex |
|---|---|---|
| LMArena Instruction Following | 1435 | — |
Long Context Not comparable
Claude Opus 4.1: 44.5 (#63), GPT-5-Codex: —
| Benchmark | Claude Opus 4.1 | GPT-5-Codex |
|---|---|---|
| LMArena Longer Query | 1455 | — |
Writing & Preference Not comparable
Claude Opus 4.1: 62.4 (#74), GPT-5-Codex: —
| Benchmark | Claude Opus 4.1 | GPT-5-Codex |
|---|---|---|
| LMArena Text | 1419 | — |
| LMArena Creative Writing | 1412 | — |
| Short-Story Creative Writing | 84.7% | — |
| LMArena Multi-Turn | 1444 | — |
Frequently asked questions
Is Claude Opus 4.1 better than GPT-5-Codex?
Claude Opus 4.1 is the stronger model overall, scoring 41.0 to 37.9 on the Noometry Index. GPT-5-Codex costs 8.7× less per token, which makes it the better buy when Claude Opus 4.1's lead doesn't matter for your workload.
Which is cheaper, Claude Opus 4.1 or GPT-5-Codex?
GPT-5-Codex is cheaper. It lists at $1.25 per million input tokens and $10 per million output tokens; Claude Opus 4.1 lists at $15 and $75.
Is Claude Opus 4.1 or GPT-5-Codex better for coding?
Claude Opus 4.1 scores higher on coding benchmarks: 44.4 versus 42.4 in the Noometry coding category.
Which has the bigger context window?
GPT-5-Codex does, with 400K tokens against 200K.
How many benchmarks do Claude Opus 4.1 and GPT-5-Codex share?
2 benchmarks have published results for both models. Claude Opus 4.1 has 48 scored results on Noometry and GPT-5-Codex has 3.