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Model comparison

Claude Opus 4.5 vs Step 3.7 Flash

Data verified

Head-to-head evidence from 20 shared benchmark results across 6 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.

64.13/100
Margin
13.4pts
← winning
50.76/100
1 category wins1 category wins

Verified leaderboard positions: Claude Opus 4.5 #19; Step 3.7 Flash unranked

BenchAlign evidence: Claude Opus 4.5 supported; Step 3.7 Flash estimated. Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.

Evidence parity. Claude Opus 4.5 and Step 3.7 Flash share 20 comparable benchmark results. 2 of 8 categories are comparable. 40 results are unique to Claude Opus 4.5; 10 to Step 3.7 Flash.

Updated July 16, 2026
Shared results
20
Claude Opus 4.5 only
40
Step 3.7 Flash only
10
Comparable categories
2 / 8

Pick Claude Opus 4.5 if you want the stronger benchmark profile. Step 3.7 Flash only becomes the better choice if agentic is the priority or you want the cheaper token bill.

Confidence note. This is a partial-evidence comparison with 20 shared benchmark results across 6 evidence categories; 2 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.

Why this result

Claude Opus 4.5 is clearly ahead on the provisional aggregate, 71 to 57. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

Claude Opus 4.5's sharpest advantage is in coding, where it averages 71.7 against 56.3. The single biggest benchmark swing on the page is SWE-bench Pro, 57.1% to 56.3%. Step 3.7 Flash does hit back in agentic, so the answer changes if that is the part of the workload you care about most.

Claude Opus 4.5 is also the more expensive model on tokens at $5.00 input / $25.00 output per 1M tokens, versus $0.20 input / $1.15 output per 1M tokens for Step 3.7 Flash. That is roughly 21.7x on output cost alone. Step 3.7 Flash is the reasoning model in the pair, while Claude Opus 4.5 is not. That usually helps on harder chain-of-thought-heavy tests, but it can also mean more latency and more token spend in real use. Step 3.7 Flash gives you the larger context window at 256K, compared with 200K for Claude Opus 4.5.

Category breakdown

Exact category averages are shown below. Not measured means BenchLM does not have enough sourced public coverage for that model and category.

Category scores and score margins for Claude Opus 4.5 and Step 3.7 Flash
CategoryClaude Opus 4.5ΔStep 3.7 Flash
CodingClaude Opus 4.571.7Margin← 15.4Step 3.7 Flash56.3
AgenticClaude Opus 4.562.6Margin→ 3.8Step 3.7 Flash66.4
ReasoningClaude Opus 4.564.4MarginNo overlapStep 3.7 FlashNot measured
KnowledgeClaude Opus 4.558.5MarginNo overlapStep 3.7 FlashNot measured
MathClaude Opus 4.557.5MarginNo overlapStep 3.7 FlashNot measured
MultilingualClaude Opus 4.585.7MarginNo overlapStep 3.7 FlashNot measured
MultimodalClaude Opus 4.569.9MarginNo overlapStep 3.7 FlashNot measured
Inst. FollowingClaude Opus 4.569.5MarginNo overlapStep 3.7 FlashNot measured

Decisive benchmark drivers

The largest measured benchmark gaps in this matchup, with exact reported values.

More
A · Claude Opus 4.5B · Step 3.7 Flash

  1. SWE-bench Pro

    Coding
    Source ↗
    A 57.1%B 56.3%
    Winner: Claude Opus 4.5Δ 0.8
    SWE-bench Pro: Claude Opus 4.5 scored 57.1%; Step 3.7 Flash scored 56.3%. Claude Opus 4.5 wins this benchmark.

  2. Terminal-Bench 2.0

    Agentic
    Source ↗
    A 59.3%B 59.5%
    Winner: Step 3.7 FlashΔ 0.2
    Terminal-Bench 2.0: Claude Opus 4.5 scored 59.3%; Step 3.7 Flash scored 59.5%. Step 3.7 Flash wins this benchmark.

Operational comparison

Runtime and commercial metrics are compared only when both models have a complete sourced value.

MetricClaude Opus 4.5Step 3.7 FlashComparison
Input / output priceUSD per 1M tokensClaude Opus 4.5$5 input / $25 outputStep 3.7 Flash$0.2 input / $1.15 outputStep 3.7 Flash has the lower combined listed price.
Generation speedtokens per secondClaude Opus 4.546 tok/sStep 3.7 FlashNot availableA complete speed comparison is not available.
First-answer latencyseconds to first tokenClaude Opus 4.51.01 sStep 3.7 FlashNot availableA complete latency comparison is not available.
Context windowmaximum listed tokensClaude Opus 4.5200KStep 3.7 Flash256KStep 3.7 Flash lists the larger context window.

Benchmark Deep Dive

AgenticStep 3.7 Flash wins
BenchmarkClaude Opus 4.5Step 3.7 FlashResult
Terminal-Bench 2.0Source 59.3%59.5%Step 3.7 Flash leads
OSWorld-VerifiedSource 66.3%—Not comparable
OSWorldSource 66.3%—Not comparable
Claw-EvalSource 59.6%67.1%Step 3.7 Flash leads
QwenClawBenchSource 52.3%—Not comparable
τ³-bench resultsSource 70.2%—Not comparable
VITA-BenchSource 23.3%—Not comparable
DeepPlanningSource 26.4%—Not comparable
ToolathlonSource 43.5%49.5%Step 3.7 Flash leads
MCP AtlasSource 42.3%—Not comparable
MCP-TasksSource 71.8%—Not comparable
WideResearchSource 76.4%—Not comparable
CyberGymSource 50.6%—Not comparable
τ²-bench resultsSource 86.3%98.5%Step 3.7 Flash leads
Gert LabsSource 64.23%51.57%Claude Opus 4.5 leads
JobBenchSource 32.3%—Not comparable
BrowseCompSource —75.8%Not comparable
DeepSearchQASource —92.8%Not comparable
GDPval-AASource —25.9%Not comparable
HLE w/ toolsSource —47.2%Not comparable
AA Agentic IndexSource —21.5%Not comparable
GDPval-AASource —1017Not comparable
APEX-Agents-AASource —14.8%Not comparable
CodingClaude Opus 4.5 wins
BenchmarkClaude Opus 4.5Step 3.7 FlashResult
SWE-bench VerifiedSource 80.9%—Not comparable
LiveCodeBench v6Source 84.8%—Not comparable
SWE-bench ProSource 57.1%56.3%Claude Opus 4.5 leads
SWE MultilingualSource 77.5%—Not comparable
NL2RepoSource 43.2%—Not comparable
Terminal-Bench HardSource 40.9%35.6%Claude Opus 4.5 leads
AA-SciCodeSource 47.0%40.0%Claude Opus 4.5 leads
Terminal-Bench 2.0Source —59.5%Not comparable
AA Coding IndexSource —39.6%Not comparable
Reasoning
BenchmarkClaude Opus 4.5Step 3.7 FlashResult
LongBench v2Source 64.4%—Not comparable
AI-NeedleSource 74%—Not comparable
AA-LCRSource 65.3%63.7%Claude Opus 4.5 leads
CritPtSource 0.3%2.3%Step 3.7 Flash leads
Knowledge
BenchmarkClaude Opus 4.5Step 3.7 FlashResult
GPQASource 87%—Not comparable
SuperGPQASource 70.6%—Not comparable
MMLU-ProSource 89.5%—Not comparable
MMLU-ReduxSource 96.6%—Not comparable
C-EvalSource 92.2%—Not comparable
HLESource 30.8%—Not comparable
Artificial Analysis Intelligence IndexSource 34.7%30.3%Claude Opus 4.5 leads
AA-GPQA DiamondSource 81.0%80.9%Claude Opus 4.5 leads
AA-HLESource 12.9%19.9%Step 3.7 Flash leads
AA-Omniscience IndexSource -3.9%-37.5%Claude Opus 4.5 leads
AA-Omniscience AccuracySource 40.7%25.4%Claude Opus 4.5 leads
AA-Omniscience Hallucination RateSource 75.4%84.4%Claude Opus 4.5 leads
AA MMLU-ProSource 88.9%—Not comparable
Math
BenchmarkClaude Opus 4.5Step 3.7 FlashResult
AIME26Source 95.1%—Not comparable
HMMT Feb 2025Source 92.9%—Not comparable
HMMT Nov 2025Source 93.3%—Not comparable
HMMT Feb 2026Source 85.3%—Not comparable
MMAnswerBenchSource 84.0%—Not comparable
FrontierMath v2 (Tiers 1-3)Source 20.690%—Not comparable
FrontierMath v2 (Tier 4)Source 4.167%—Not comparable
Multilingual
BenchmarkClaude Opus 4.5Step 3.7 FlashResult
MMLU-ProXSource 85.7%—Not comparable
NOVA-63Source 56.7%—Not comparable
Multimodal
BenchmarkClaude Opus 4.5Step 3.7 FlashResult
MMMU-ProSource 70.6%—Not comparable
MathVisionSource 74.3%—Not comparable
CharXivSource 68.5%—Not comparable
VideoMMMUSource 84.4%—Not comparable
ScreenSpot ProSource 45.7%—Not comparable
V*Source 67.0%95.3%Step 3.7 Flash leads
AA-MMMU-ProSource 71.2%75.3%Step 3.7 Flash leads
Design Arena WebsiteSource 12811218Claude Opus 4.5 leads
SimpleVQASource —79.2%Not comparable
Inst. Following
BenchmarkClaude Opus 4.5Step 3.7 FlashResult
IFEvalSource 90.9%—Not comparable
IFBenchSource 58%—Not comparable
AA-IFBenchSource 43.0%67.3%Step 3.7 Flash leads
Frequently Asked Questions (3)

Which is better, Claude Opus 4.5 or Step 3.7 Flash?

Claude Opus 4.5 is ahead on BenchLM's provisional leaderboard, 71 to 57. The biggest single separator in this matchup is SWE-bench Pro, where the scores are 57.1% and 56.3%.

Which is better for coding, Claude Opus 4.5 or Step 3.7 Flash?

Claude Opus 4.5 has the edge for coding in this comparison, averaging 71.7 versus 56.3. Inside this category, AA-SciCode is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, Claude Opus 4.5 or Step 3.7 Flash?

Step 3.7 Flash has the edge for agentic tasks in this comparison, averaging 66.4 versus 62.6. Inside this category, Gert Labs is the benchmark that creates the most daylight between them.

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