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Model comparison

Claude Opus 4.5 vs DeepSeek V4 Flash

Data verified

Head-to-head evidence from 13 shared benchmark results across 5 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.

64.22/100
Margin
5.3pts
← winning
58.88/100
4 category wins0 category wins

Public leaderboard positions: Claude Opus 4.5 #34 (Supported); DeepSeek V4 Flash #61 (Estimated). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.

Evidence parity. Claude Opus 4.5 and DeepSeek V4 Flash share 13 comparable benchmark results. 4 of 8 categories are comparable. 46 results are unique to Claude Opus 4.5; 9 to DeepSeek V4 Flash.

Updated July 23, 2026
Shared results
13
Claude Opus 4.5 only
46
DeepSeek V4 Flash only
9
Comparable categories
4 / 8

Pick Claude Opus 4.5 if you want the stronger benchmark profile. DeepSeek V4 Flash only becomes the better choice if you want the cheaper token bill or you need the larger 1M context window.

Confidence note. This is a partial-evidence comparison with 13 shared benchmark results across 5 evidence categories; 4 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 BenchAlign aggregate, 64.22 to 58.88. 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 knowledge, where it averages 58.1 against 38.8. The single biggest benchmark swing on the page is HMMT Feb 2026, 85.3% to 40.8%.

Claude Opus 4.5 is also the more expensive model on tokens at $5.00 input / $25.00 output per 1M tokens, versus $0.14 input / $0.28 output per 1M tokens for DeepSeek V4 Flash. That is roughly 89.3x on output cost alone. DeepSeek V4 Flash gives you the larger context window at 1M, 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 DeepSeek V4 Flash
CategoryClaude Opus 4.5ΔDeepSeek V4 Flash
KnowledgeClaude Opus 4.558.1Margin← 19.3DeepSeek V4 Flash38.8
MathClaude Opus 4.557.5Margin← 16.7DeepSeek V4 Flash40.8
AgenticClaude Opus 4.562.6Margin← 13.5DeepSeek V4 Flash49.1
CodingClaude Opus 4.571.7Margin← 7.5DeepSeek V4 Flash64.2
ReasoningClaude Opus 4.564.4MarginNo overlapDeepSeek V4 FlashNot measured
MultilingualClaude Opus 4.585.7MarginNo overlapDeepSeek V4 FlashNot measured
MultimodalClaude Opus 4.569.9MarginNo overlapDeepSeek V4 FlashNot measured
Inst. FollowingClaude Opus 4.569.5MarginNo overlapDeepSeek V4 FlashNot measured

Decisive benchmark drivers

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

More
A · Claude Opus 4.5B · DeepSeek V4 Flash

  1. HMMT Feb 2026

    Math
    Source ↗
    A 85.3%B 40.8%
    Winner: Claude Opus 4.5Δ 44.5
    HMMT Feb 2026: Claude Opus 4.5 scored 85.3%; DeepSeek V4 Flash scored 40.8%. Claude Opus 4.5 wins this benchmark.

  2. HLE

    Knowledge
    Source ↗
    A 30.8%B 8.1%
    Winner: Claude Opus 4.5Δ 22.7
    HLE: Claude Opus 4.5 scored 30.8%; DeepSeek V4 Flash scored 8.1%. Claude Opus 4.5 wins this benchmark.

  3. GPQA

    Knowledge
    Source ↗
    A 87%B 71.2%
    Winner: Claude Opus 4.5Δ 15.8
    GPQA: Claude Opus 4.5 scored 87%; DeepSeek V4 Flash scored 71.2%. Claude Opus 4.5 wins this benchmark.

  4. Terminal-Bench 2.0

    Agentic
    Source ↗
    A 59.3%B 49.1%
    Winner: Claude Opus 4.5Δ 10.2
    Terminal-Bench 2.0: Claude Opus 4.5 scored 59.3%; DeepSeek V4 Flash scored 49.1%. Claude Opus 4.5 wins this benchmark.

  5. SWE-bench Pro

    Coding
    Source ↗
    A 57.1%B 49.1%
    Winner: Claude Opus 4.5Δ 8
    SWE-bench Pro: Claude Opus 4.5 scored 57.1%; DeepSeek V4 Flash scored 49.1%. Claude Opus 4.5 wins this benchmark.

Operational comparison

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

MetricClaude Opus 4.5DeepSeek V4 FlashComparison
Input / output priceUSD per 1M tokensClaude Opus 4.5$5 input / $25 outputDeepSeek V4 Flash$0.14 input / $0.28 outputDeepSeek V4 Flash has the lower combined listed price.
Generation speedtokens per secondClaude Opus 4.546 tok/sDeepSeek V4 FlashNot availableA complete speed comparison is not available.
First-answer latencyseconds to first tokenClaude Opus 4.51.01 sDeepSeek V4 FlashNot availableA complete latency comparison is not available.
Context windowmaximum listed tokensClaude Opus 4.5200KDeepSeek V4 Flash1MDeepSeek V4 Flash lists the larger context window.

Benchmark Deep Dive

AgenticClaude Opus 4.5 wins
BenchmarkClaude Opus 4.5DeepSeek V4 FlashResult
Terminal-Bench 2.0Source 59.3%49.1%Claude Opus 4.5 leads
OSWorld-VerifiedSource 66.3%—Not comparable
OSWorldSource 66.3%—Not comparable
Claw-EvalSource 59.6%57.8%Claude Opus 4.5 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%40.7%Claude Opus 4.5 leads
MCP AtlasSource 42.3%64%DeepSeek V4 Flash leads
MCP-TasksSource 71.8%—Not comparable
WideResearchSource 76.4%—Not comparable
CyberGymSource 50.6%—Not comparable
τ²-bench resultsSource 86.3%—Not comparable
Gert LabsSource 64.23%54.35%Claude Opus 4.5 leads
JobBenchSource 32.3%—Not comparable
CodingClaude Opus 4.5 wins
BenchmarkClaude Opus 4.5DeepSeek V4 FlashResult
SWE-bench VerifiedSource 80.9%73.7%Claude Opus 4.5 leads
LiveCodeBench v6Source 84.8%—Not comparable
SWE-bench ProSource 57.1%49.1%Claude Opus 4.5 leads
SWE MultilingualSource 77.5%69.7%Claude Opus 4.5 leads
NL2RepoSource 43.2%—Not comparable
AA-SciCodeSource 47.0%—Not comparable
Terminal-Bench 2.0Source —49.1%Not comparable
Reasoning
BenchmarkClaude Opus 4.5DeepSeek V4 FlashResult
LongBench v2Source 64.4%—Not comparable
AI-NeedleSource 74%—Not comparable
AA-LCRSource 65.3%—Not comparable
CritPtSource 0.3%—Not comparable
MRCR 1MSource —37.5%Not comparable
CorpusQA 1MSource —15.5%Not comparable
KnowledgeClaude Opus 4.5 wins
BenchmarkClaude Opus 4.5DeepSeek V4 FlashResult
GPQASource 87%71.2%Claude Opus 4.5 leads
SuperGPQASource 70.6%—Not comparable
MMLU-ProSource 89.5%83%Claude Opus 4.5 leads
MMLU-ReduxSource 96.6%—Not comparable
C-EvalSource 92.2%—Not comparable
HLESource 30.8%8.1%Claude Opus 4.5 leads
Artificial Analysis Intelligence IndexSource 34.7%—Not comparable
AA-GPQA DiamondSource 81.0%—Not comparable
AA-HLESource 12.9%—Not comparable
AA-Omniscience IndexSource -3.9%—Not comparable
AA-Omniscience AccuracySource 40.7%—Not comparable
AA-Omniscience Hallucination RateSource 75.4%—Not comparable
AA MMLU-ProSource 88.9%—Not comparable
SimpleQASource —23.1%Not comparable
Chinese-SimpleQASource —71.5%Not comparable
GPQA-DSource —71.2%Not comparable
MathClaude Opus 4.5 wins
BenchmarkClaude Opus 4.5DeepSeek V4 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%40.8%Claude Opus 4.5 leads
MMAnswerBenchSource 84.0%—Not comparable
FrontierMath v2 (Tiers 1-3)Source 20.690%—Not comparable
FrontierMath v2 (Tier 4)Source 4.167%—Not comparable
IMOAnswerBenchSource —41.9%Not comparable
ApexSource —1.0%Not comparable
Apex ShortlistSource —9.3%Not comparable
Multilingual
BenchmarkClaude Opus 4.5DeepSeek V4 FlashResult
MMLU-ProXSource 85.7%—Not comparable
NOVA-63Source 56.7%—Not comparable
Multimodal
BenchmarkClaude Opus 4.5DeepSeek V4 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%—Not comparable
AA-MMMU-ProSource 71.2%—Not comparable
Design Arena WebsiteSource 12771238Claude Opus 4.5 leads
Inst. Following
BenchmarkClaude Opus 4.5DeepSeek V4 FlashResult
IFEvalSource 90.9%—Not comparable
IFBenchSource 58%—Not comparable
AA-IFBenchSource 43.0%—Not comparable
Frequently Asked Questions (5)

Which is better, Claude Opus 4.5 or DeepSeek V4 Flash?

Claude Opus 4.5 is ahead on BenchLM's BenchAlign leaderboard, 64.22 to 58.88. The biggest single separator in this matchup is HMMT Feb 2026, where the scores are 85.3% and 40.8%.

Which is better for knowledge tasks, Claude Opus 4.5 or DeepSeek V4 Flash?

Claude Opus 4.5 has the edge for knowledge tasks in this comparison, averaging 58.1 versus 38.8. Inside this category, HLE is the benchmark that creates the most daylight between them.

Which is better for coding, Claude Opus 4.5 or DeepSeek V4 Flash?

Claude Opus 4.5 has the edge for coding in this comparison, averaging 71.7 versus 64.2. Inside this category, SWE-bench Pro is the benchmark that creates the most daylight between them.

Which is better for math, Claude Opus 4.5 or DeepSeek V4 Flash?

Claude Opus 4.5 has the edge for math in this comparison, averaging 57.5 versus 40.8. Inside this category, HMMT Feb 2026 is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, Claude Opus 4.5 or DeepSeek V4 Flash?

Claude Opus 4.5 has the edge for agentic tasks in this comparison, averaging 62.6 versus 49.1. Inside this category, MCP Atlas is the benchmark that creates the most daylight between them.

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