Model comparison
Claude Opus 4.5 vs Step 3.7 Flash
Claude Opus 4.5 is the stronger model overall, scoring 50.5 to 37.3 on the Noometry Index. Step 3.7 Flash costs 24× less per token, which makes it the better buy when Claude Opus 4.5's lead doesn't matter for your workload.
Last verified . 2 shared benchmarks.
StepFunSummary
- They share 2 benchmarks with published results for both. Claude Opus 4.5 scores higher in 2 categories and Step 3.7 Flash in 1 category; 3 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where Claude Opus 4.5 leads 42.6 to 21.6.
- The biggest single-benchmark swing is NYT Connections (extended): 52.5% for Claude Opus 4.5 and 39.7% for Step 3.7 Flash.
- Step 3.7 Flash is cheaper at $0.18 / $1.11 per million input/output tokens, against $5 / $25 for Claude Opus 4.5.
- Step 3.7 Flash accepts more context: 256K tokens versus 200K.
- Step 3.7 Flash has downloadable open weights; the other is API-only.
Side by side
| Claude Opus 4.5 | Step 3.7 Flash | |
|---|---|---|
| Provider | Anthropic | StepFun |
| Noometry Index | 50.5 | 37.3 |
| Released | 2025-11-01 | 2026-05-29 |
| Weights | Proprietary | Open |
| Context window | 200K | 256K |
| Max output | 64K | 256K |
| Input $ / M tokens | $5 | $0.18 |
| Output $ / M tokens | $25 | $1.11 |
| Results tracked | 69 | 5 |
Sponsored placements are available on pages like this one. Advertise on Noometry
Category by category
Coding Claude Opus 4.5 leads
Claude Opus 4.5: 54.8 (#27), Step 3.7 Flash: 40.0 (#150)
| Benchmark | Claude Opus 4.5 | Step 3.7 Flash |
|---|---|---|
| ALE-Bench | 1,025 | 694.12 |
| SWE-bench Verified | 76.7% | — |
| SWE-bench Verified (bash only) | 76.8% | — |
| LMArena WebDev | 1494 | — |
| SWE-bench Multilingual | 70.7% | — |
| SciCode | — | 40% |
| GSO | 26.5% | — |
| WeirdML | 63.7% | — |
| LMArena Coding | 1504 | — |
| AlgoTune | 1.77 | — |
Agentic & Tool Use Not comparable
Claude Opus 4.5: 47.3 (#12), Step 3.7 Flash: —
| Benchmark | Claude Opus 4.5 | Step 3.7 Flash |
|---|---|---|
| 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 3.7 Flash: 21.6 (#219)
| Benchmark | Claude Opus 4.5 | Step 3.7 Flash |
|---|---|---|
| NYT Connections (extended) | 52.5% | 39.7% |
| ARC-AGI-2 | 37.6% | — |
| SimpleBench | 62% | — |
| Kagi LLM Benchmark | 80.2% | — |
| ARC-AGI-1 | 80% | — |
| CritPt | — | 2.3% |
| Chess Puzzles | 12% | — |
| EnigmaEval | 11.9% | — |
| EBR-Bench | 14.3% | — |
| LMArena Hard Prompts | 1476 | — |
| Mystery Game Puzzles | 22% | — |
| DTBench | 89.9% | — |
| LMCA | 44.5% | — |
| Epoch Capabilities Index | 150.09 | — |
| ForecastBench | 60.7 | — |
Math Step 3.7 Flash leads
Claude Opus 4.5: 38.6 (#132), Step 3.7 Flash: 42.9 (#82)
| Benchmark | Claude Opus 4.5 | Step 3.7 Flash |
|---|---|---|
| FrontierMath (Tiers 1-3) | 34.4% | — |
| FrontierMath Tier 4 | 4.9% | — |
| MathArena Final-Answer Competitions | — | 68.5% |
| OTIS Mock AIME 2024-2025 | 86.1% | — |
| ProofBench | 36% | — |
| LMArena Math | 1463 | — |
| FrontierMath (Feb 2025 set) | 20.7% | — |
| FrontierMath Tier 4 (v1) | 4.2% | — |
Knowledge Not comparable
Claude Opus 4.5: 56.5 (#44), Step 3.7 Flash: —
| Benchmark | Claude Opus 4.5 | Step 3.7 Flash |
|---|---|---|
| GPQA Diamond | 86% | — |
| Humanity's Last Exam | 25.2% | — |
| SimpleQA Verified | 45.7% | — |
| Vectara Hallucination Rate | 10.9% | — |
| LMArena Expert | 1487 | — |
Multimodal Not comparable
Claude Opus 4.5: 31.4 (#107), Step 3.7 Flash: —
| Benchmark | Claude Opus 4.5 | Step 3.7 Flash |
|---|---|---|
| GeoBench | 75% | — |
| VPCT | 40% | — |
| Furniture Assembly | 28.3% | — |
| LMArena Document | 1462 | — |
Multilingual Not comparable
Claude Opus 4.5: 54.3 (#47), Step 3.7 Flash: —
| Benchmark | Claude Opus 4.5 | Step 3.7 Flash |
|---|---|---|
| LMArena Non-English | 1438 | — |
| LMArena Chinese | 1470 | — |
| LMArena French | 1471 | — |
| LMArena German | 1449 | — |
| LMArena Japanese | 1416 | — |
| LMArena Korean | 1424 | — |
| LMArena Russian | 1447 | — |
| LMArena Spanish | 1458 | — |
Instruction Following Not comparable
Claude Opus 4.5: 77.5 (#19), Step 3.7 Flash: —
| Benchmark | Claude Opus 4.5 | Step 3.7 Flash |
|---|---|---|
| LMArena Instruction Following | 1478 | — |
Long Context Not comparable
Claude Opus 4.5: 46.5 (#22), Step 3.7 Flash: —
| Benchmark | Claude Opus 4.5 | Step 3.7 Flash |
|---|---|---|
| CL-bench | 21.1% | — |
| LMArena Longer Query | 1480 | — |
Writing & Preference Not comparable
Claude Opus 4.5: 68.1 (#28), Step 3.7 Flash: —
| Benchmark | Claude Opus 4.5 | Step 3.7 Flash |
|---|---|---|
| LMArena Text | 1451 | — |
| LMArena Creative Writing | 1445 | — |
| EQ-Bench Creative Writing | 1687 | — |
| LMArena Multi-Turn | 1466 | — |
Frequently asked questions
Is Claude Opus 4.5 better than Step 3.7 Flash?
Claude Opus 4.5 is the stronger model overall, scoring 50.5 to 37.3 on the Noometry Index. Step 3.7 Flash costs 24× 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 3.7 Flash?
Step 3.7 Flash is cheaper. It lists at $0.18 per million input tokens and $1.11 per million output tokens; Claude Opus 4.5 lists at $5 and $25.
Is Claude Opus 4.5 or Step 3.7 Flash better for coding?
Claude Opus 4.5 scores higher on coding benchmarks: 54.8 versus 40.0 in the Noometry coding category.
Which has the bigger context window?
Step 3.7 Flash does, with 256K tokens against 200K.
How many benchmarks do Claude Opus 4.5 and Step 3.7 Flash share?
2 benchmarks have published results for both models. Claude Opus 4.5 has 69 scored results on Noometry and Step 3.7 Flash has 5.