Model comparison
Claude Opus 4.5 vs GPT-5.3 Chat
Claude Opus 4.5 is the stronger model overall, scoring 50.5 to 42.1 on the Noometry Index. GPT-5.3 Chat costs 2.1× less per token, which makes it the better buy when Claude Opus 4.5's lead doesn't matter for your workload.
Last verified . 18 shared benchmarks.
Summary
- They share 18 benchmarks with published results for both. Claude Opus 4.5 scores higher in 8 categories and GPT-5.3 Chat in 0 categories; 8 gaps are clear of the uncertainty.
- The widest gap is in knowledge, where Claude Opus 4.5 leads 56.4 to 38.2.
- GPT-5.3 Chat is cheaper at $1.75 / $14 per million input/output tokens, against $5 / $25 for Claude Opus 4.5.
- Claude Opus 4.5 accepts more context: 200K tokens versus 128K.
Side by side
| Claude Opus 4.5 | GPT-5.3 Chat | |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Noometry Index | 50.5 | 42.1 |
| Released | 2025-11-01 | 2026-03-03 |
| Weights | Proprietary | Proprietary |
| Context window | 200K | 128K |
| Max output | 64K | 16K |
| Input $ / M tokens | $5 | $1.75 |
| Output $ / M tokens | $25 | $14 |
| Results tracked | 69 | 18 |
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Category by category
Coding Claude Opus 4.5 leads
Claude Opus 4.5: 55.4 (#21), GPT-5.3 Chat: 40.8 (#124)
| Benchmark | Claude Opus 4.5 | GPT-5.3 Chat |
|---|---|---|
| LMArena Coding | 1504 | 1408 |
| SWE-bench Verified | 76.7% | — |
| SWE-bench Verified (bash only) | 76.8% | — |
| LMArena WebDev | 1493 | — |
| SWE-bench Multilingual | 70.7% | — |
| GSO | 26.5% | — |
| WeirdML | 63.7% | — |
| ALE-Bench | 1,025 | — |
| AlgoTune | 1.77 | — |
Agentic & Tool Use Not comparable
Claude Opus 4.5: 47.2 (#11), GPT-5.3 Chat: —
| Benchmark | Claude Opus 4.5 | GPT-5.3 Chat |
|---|---|---|
| Terminal-Bench | 63.1% | — |
| Berkeley Function Calling Leaderboard | 77.5% | — |
| GDPval | 45.5% | — |
| Remote Labor Index | 3.8% | — |
| τ²-bench Airline | 84% | — |
| τ²-bench Banking | 24.7% | — |
| τ²-bench Retail | 79.6% | — |
| τ²-bench Telecom | 92.3% | — |
| Cybench | 82% | — |
| DeepResearch Bench | 54.8% | — |
| OSWorld | 66.3% | — |
| BALROG | 43.5% | — |
| LMArena Search | 1180 | — |
| METR Time Horizons | 75% | — |
| Vending-Bench 2 | 4,967 | — |
Reasoning Claude Opus 4.5 leads
Claude Opus 4.5: 42.5 (#43), GPT-5.3 Chat: 27.3 (#105)
| Benchmark | Claude Opus 4.5 | GPT-5.3 Chat |
|---|---|---|
| LMArena Hard Prompts | 1476 | 1399 |
| ARC-AGI-2 | 37.6% | — |
| SimpleBench | 62% | — |
| Kagi LLM Benchmark | 80.2% | — |
| NYT Connections (extended) | 52.5% | — |
| ARC-AGI-1 | 80% | — |
| Chess Puzzles | 12% | — |
| EnigmaEval | 11.9% | — |
| EBR-Bench | 14.3% | — |
| Mystery Game Puzzles | 22% | — |
| DTBench | 89.9% | — |
| LMCA | 44.5% | — |
| Epoch Capabilities Index | 150.1 | — |
| ForecastBench | 60.7 | — |
Math Claude Opus 4.5 leads
Claude Opus 4.5: 38.5 (#85), GPT-5.3 Chat: 35.4 (#146)
| Benchmark | Claude Opus 4.5 | GPT-5.3 Chat |
|---|---|---|
| LMArena Math | 1463 | 1389 |
| FrontierMath (Tiers 1-3) | 34.4% | — |
| FrontierMath Tier 4 | 4.9% | — |
| OTIS Mock AIME 2024-2025 | 86.1% | — |
| ProofBench | 36% | — |
| FrontierMath (Feb 2025 set) | 20.7% | — |
| FrontierMath Tier 4 (v1) | 4.2% | — |
Knowledge Claude Opus 4.5 leads
Claude Opus 4.5: 56.4 (#38), GPT-5.3 Chat: 38.2 (#137)
| Benchmark | Claude Opus 4.5 | GPT-5.3 Chat |
|---|---|---|
| LMArena Expert | 1488 | 1397 |
| GPQA Diamond | 86% | — |
| Humanity's Last Exam | 25.2% | — |
| SimpleQA Verified | 45.7% | — |
| Vectara Hallucination Rate | 10.9% | — |
Multimodal Not comparable
Claude Opus 4.5: 31.1 (#99), GPT-5.3 Chat: —
| Benchmark | Claude Opus 4.5 | GPT-5.3 Chat |
|---|---|---|
| GeoBench | 75% | — |
| VPCT | 40% | — |
| Furniture Assembly | 28.3% | — |
| LMArena Document | 1462 | — |
Multilingual Claude Opus 4.5 leads
Claude Opus 4.5: 54.5 (#45), GPT-5.3 Chat: 50.5 (#119)
| Benchmark | Claude Opus 4.5 | GPT-5.3 Chat |
|---|---|---|
| LMArena Non-English | 1438 | 1383 |
| LMArena Chinese | 1470 | 1433 |
| LMArena French | 1471 | 1398 |
| LMArena German | 1449 | 1384 |
| LMArena Japanese | 1415 | 1351 |
| LMArena Korean | 1424 | 1347 |
| LMArena Russian | 1448 | 1400 |
| LMArena Spanish | 1455 | 1371 |
Instruction Following Claude Opus 4.5 leads
Claude Opus 4.5: 77.7 (#20), GPT-5.3 Chat: 73.0 (#124)
| Benchmark | Claude Opus 4.5 | GPT-5.3 Chat |
|---|---|---|
| LMArena Instruction Following | 1478 | 1378 |
Long Context Claude Opus 4.5 leads
Claude Opus 4.5: 46.4 (#21), GPT-5.3 Chat: 42.6 (#115)
| Benchmark | Claude Opus 4.5 | GPT-5.3 Chat |
|---|---|---|
| LMArena Longer Query | 1480 | 1396 |
| CL-bench | 21.1% | — |
Writing & Preference Claude Opus 4.5 leads
Claude Opus 4.5: 68.2 (#28), GPT-5.3 Chat: 63.3 (#65)
| Benchmark | Claude Opus 4.5 | GPT-5.3 Chat |
|---|---|---|
| LMArena Text | 1451 | 1389 |
| LMArena Creative Writing | 1445 | 1356 |
| EQ-Bench Creative Writing | 1687 | 1690 |
| LMArena Multi-Turn | 1466 | 1413 |
Frequently asked questions
Is Claude Opus 4.5 better than GPT-5.3 Chat?
Claude Opus 4.5 is the stronger model overall, scoring 50.5 to 42.1 on the Noometry Index. GPT-5.3 Chat costs 2.1× less per token, which makes it the better buy when Claude Opus 4.5's lead doesn't matter for your workload.
Which is cheaper, Claude Opus 4.5 or GPT-5.3 Chat?
GPT-5.3 Chat is cheaper. It lists at $1.75 per million input tokens and $14 per million output tokens; Claude Opus 4.5 lists at $5 and $25.
Is Claude Opus 4.5 or GPT-5.3 Chat better for coding?
Claude Opus 4.5 scores higher on coding benchmarks: 55.4 versus 40.8 in the Noometry coding category.
Which has the bigger context window?
Claude Opus 4.5 does, with 200K tokens against 128K.
How many benchmarks do Claude Opus 4.5 and GPT-5.3 Chat share?
18 benchmarks have published results for both models. Claude Opus 4.5 has 69 scored results on Noometry and GPT-5.3 Chat has 18.