Model comparison
Claude Opus 4.5 vs Step 5 Preview
Claude Opus 4.5 is the stronger model overall, scoring 50.5 to 47.9 on the Noometry Index. Step 5 Preview costs 7.0× less per token, which makes it the better buy when Claude Opus 4.5's lead doesn't matter for your workload.
Last verified . 15 shared benchmarks.
StepFunSummary
- They share 15 benchmarks with published results for both. Claude Opus 4.5 scores higher in 7 categories and Step 5 Preview in 2 categories; 8 gaps are clear of the uncertainty.
- The widest gap is in knowledge, where Claude Opus 4.5 leads 56.5 to 41.2.
- The biggest single-benchmark swing is ProofBench: 36% for Claude Opus 4.5 and 42% for Step 5 Preview.
- Step 5 Preview is cheaper at $1 / $2.70 per million input/output tokens, against $5 / $25 for Claude Opus 4.5.
- Step 5 Preview accepts more context: 1.02M tokens versus 200K.
Side by side
| Claude Opus 4.5 | Step 5 Preview | |
|---|---|---|
| Provider | Anthropic | StepFun |
| Noometry Index | 50.5 | 47.9 |
| Released | 2025-11-01 | 2026-09-16 |
| Weights | Proprietary | Proprietary |
| Context window | 200K | 1.02M |
| Max output | 64K | 66K |
| Input $ / M tokens | $5 | $1 |
| Output $ / M tokens | $25 | $2.70 |
| Results tracked | 69 | 18 |
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Category by category
Coding Claude Opus 4.5 leads
Claude Opus 4.5: 54.8 (#27), Step 5 Preview: 51.8 (#36)
| Benchmark | Claude Opus 4.5 | Step 5 Preview |
|---|---|---|
| LMArena WebDev | 1494 | 1564 |
| LMArena Coding | 1504 | 1480 |
| SWE-bench Verified | 76.7% | — |
| SWE-bench Verified (bash only) | 76.8% | — |
| SWE-bench Multilingual | 70.7% | — |
| SciCode | — | 58.9% |
| GSO | 26.5% | — |
| WeirdML | 63.7% | — |
| ALE-Bench | 1,025 | — |
| AlgoTune | 1.77 | — |
Agentic & Tool Use Not comparable
Claude Opus 4.5: 47.3 (#12), Step 5 Preview: —
| Benchmark | Claude Opus 4.5 | Step 5 Preview |
|---|---|---|
| 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: 42.6 (#51), Step 5 Preview: 40.0 (#57)
| Benchmark | Claude Opus 4.5 | Step 5 Preview |
|---|---|---|
| LMArena Hard Prompts | 1476 | 1465 |
| ARC-AGI-2 | 37.6% | — |
| SimpleBench | 62% | — |
| Kagi LLM Benchmark | 80.2% | — |
| NYT Connections (extended) | 52.5% | — |
| ARC-AGI-1 | 80% | — |
| CritPt | — | 20.9% |
| Chess Puzzles | 12% | — |
| EnigmaEval | 11.9% | — |
| EBR-Bench | 14.3% | — |
| Mystery Game Puzzles | 22% | — |
| DTBench | 89.9% | — |
| LMCA | 44.5% | — |
| Epoch Capabilities Index | 150.09 | — |
| ForecastBench | 60.7 | — |
Math Step 5 Preview leads
Claude Opus 4.5: 38.6 (#132), Step 5 Preview: 46.1 (#72)
| Benchmark | Claude Opus 4.5 | Step 5 Preview |
|---|---|---|
| ProofBench | 36% | 42% |
| LMArena Math | 1463 | 1470 |
| FrontierMath (Tiers 1-3) | 34.4% | — |
| FrontierMath Tier 4 | 4.9% | — |
| OTIS Mock AIME 2024-2025 | 86.1% | — |
| FrontierMath (Feb 2025 set) | 20.7% | — |
| FrontierMath Tier 4 (v1) | 4.2% | — |
Knowledge Claude Opus 4.5 leads
Claude Opus 4.5: 56.5 (#44), Step 5 Preview: 41.2 (#112)
| Benchmark | Claude Opus 4.5 | Step 5 Preview |
|---|---|---|
| LMArena Expert | 1487 | 1470 |
| GPQA Diamond | 86% | — |
| Humanity's Last Exam | 25.2% | — |
| SimpleQA Verified | 45.7% | — |
| Vectara Hallucination Rate | 10.9% | — |
Multimodal Step 5 Preview leads
Claude Opus 4.5: 31.4 (#107), Step 5 Preview: 41.0 (#41)
| Benchmark | Claude Opus 4.5 | Step 5 Preview |
|---|---|---|
| LMArena Vision | — | 1267 |
| GeoBench | 75% | — |
| VPCT | 40% | — |
| Furniture Assembly | 28.3% | — |
| LMArena Document | 1462 | — |
Multilingual Too close to call
Claude Opus 4.5: 54.3 (#47), Step 5 Preview: 53.8 (#54)
| Benchmark | Claude Opus 4.5 | Step 5 Preview |
|---|---|---|
| LMArena Non-English | 1438 | 1432 |
| LMArena Chinese | 1470 | 1519 |
| LMArena Russian | 1447 | 1436 |
| LMArena Spanish | 1458 | 1439 |
| LMArena French | 1471 | — |
| LMArena German | 1449 | — |
| LMArena Japanese | 1416 | — |
| LMArena Korean | 1424 | — |
Instruction Following Claude Opus 4.5 leads
Claude Opus 4.5: 77.5 (#19), Step 5 Preview: 76.0 (#50)
| Benchmark | Claude Opus 4.5 | Step 5 Preview |
|---|---|---|
| LMArena Instruction Following | 1478 | 1444 |
Long Context Claude Opus 4.5 leads
Claude Opus 4.5: 46.5 (#22), Step 5 Preview: 44.5 (#64)
| Benchmark | Claude Opus 4.5 | Step 5 Preview |
|---|---|---|
| LMArena Longer Query | 1480 | 1455 |
| CL-bench | 21.1% | — |
Writing & Preference Claude Opus 4.5 leads
Claude Opus 4.5: 68.1 (#28), Step 5 Preview: 62.8 (#71)
| Benchmark | Claude Opus 4.5 | Step 5 Preview |
|---|---|---|
| LMArena Text | 1451 | 1442 |
| LMArena Creative Writing | 1445 | 1410 |
| LMArena Multi-Turn | 1466 | 1447 |
| EQ-Bench Creative Writing | 1687 | — |
Frequently asked questions
Is Claude Opus 4.5 better than Step 5 Preview?
Claude Opus 4.5 is the stronger model overall, scoring 50.5 to 47.9 on the Noometry Index. Step 5 Preview costs 7.0× 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 Step 5 Preview?
Step 5 Preview is cheaper. It lists at $1 per million input tokens and $2.70 per million output tokens; Claude Opus 4.5 lists at $5 and $25.
Is Claude Opus 4.5 or Step 5 Preview better for coding?
Claude Opus 4.5 scores higher on coding benchmarks: 54.8 versus 51.8 in the Noometry coding category.
Which has the bigger context window?
Step 5 Preview does, with 1.02M tokens against 200K.
How many benchmarks do Claude Opus 4.5 and Step 5 Preview share?
15 benchmarks have published results for both models. Claude Opus 4.5 has 69 scored results on Noometry and Step 5 Preview has 18.