Noometry

Model comparison

Claude Sonnet 4.5 vs DeepSeek V4.1 Flash

DeepSeek V4.1 Flash is the stronger model overall, scoring 52.8 to 44.1 on the Noometry Index.

Last verified . 32 shared benchmarks.

Claude Sonnet 4.5 Anthropic

44.1

Rank #81 Confirmed

DeepSeek V4.1 Flash DeepSeek

52.8

Rank #38 Confirmed

Summary

  • They share 32 benchmarks with published results for both. Claude Sonnet 4.5 scores higher in 3 categories and DeepSeek V4.1 Flash in 7 categories; 9 gaps are clear of the uncertainty.
  • The widest gap is in math, where DeepSeek V4.1 Flash leads 66.7 to 32.3.
  • The biggest single-benchmark swing is NYT Connections (extended): 37.3% for Claude Sonnet 4.5 and 89.6% for DeepSeek V4.1 Flash.
  • DeepSeek V4.1 Flash is cheaper at $0.15 / $0.60 per million input/output tokens, against $3 / $15 for Claude Sonnet 4.5.
  • DeepSeek V4.1 Flash accepts more context: 1M tokens versus 200K.
  • DeepSeek V4.1 Flash has downloadable open weights; the other is API-only.

Side by side

Claude Sonnet 4.5DeepSeek V4.1 Flash
ProviderAnthropicDeepSeek
Noometry Index44.152.8
Released2025-09-292026-09-09
WeightsProprietaryOpen
Context window200K1M
Max output64K393K
Input $ / M tokens$3$0.15
Output $ / M tokens$15$0.60
Results tracked7337

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Category by category

Coding DeepSeek V4.1 Flash leads

Claude Sonnet 4.5: 47.3 (#61), DeepSeek V4.1 Flash: 52.9 (#32)

BenchmarkClaude Sonnet 4.5DeepSeek V4.1 Flash
LMArena WebDev13931619
SciCode44.7%51.9%
LMArena Coding14891506
ALE-Bench796.151,092
SWE-bench Verified71.3%—
SWE-bench Verified (bash only)71.4%—
SWE-bench Multilingual67%—
GSO14.7%—
WeirdML47.7%—
AlgoTune1.52—

Agentic & Tool Use Claude Sonnet 4.5 leads

Claude Sonnet 4.5: 38.3 (#32), DeepSeek V4.1 Flash: 31.2 (#69)

BenchmarkClaude Sonnet 4.5DeepSeek V4.1 Flash
Terminal-Bench46.5%—
APEX-Agents—39.5%
Berkeley Function Calling Leaderboard73.2%—
GDPval42.5%—
Remote Labor Index2.1%—
τ²-bench Airline72%—
τ²-bench Banking25.3%—
τ²-bench Retail72.4%—
τ²-bench Telecom84.9%—
Cybench60%—
DeepResearch Bench52.6%—
OSWorld62.9%—
GDP.pdf—19.8%
LMArena Search1159—
METR Time Horizons67.4%—
Vending-Bench 23,839—

Reasoning DeepSeek V4.1 Flash leads

Claude Sonnet 4.5: 26.9 (#125), DeepSeek V4.1 Flash: 50.2 (#36)

BenchmarkClaude Sonnet 4.5DeepSeek V4.1 Flash
NYT Connections (extended)37.3%89.6%
CritPt1.1%14.3%
LMArena Hard Prompts14621483
Mystery Game Puzzles17%43%
DTBench83.2%89.9%
LMCA38.8%47%
Epoch Capabilities Index146.84154.9
ARC-AGI-213.6%—
SimpleBench54.3%—
Kagi LLM Benchmark57.9%—
ARC-AGI-163.7%—
Chess Puzzles12%—
EnigmaEval6%—
EBR-Bench2.4%—
Surface Evolver Bench—46.3%
ForecastBench61.9—

Math DeepSeek V4.1 Flash leads

Claude Sonnet 4.5: 32.3 (#216), DeepSeek V4.1 Flash: 66.7 (#25)

BenchmarkClaude Sonnet 4.5DeepSeek V4.1 Flash
FrontierMath (Tiers 1-3)23.9%67.4%
FrontierMath Tier 42.4%26.8%
OTIS Mock AIME 2024-202577.8%98.3%
ProofBench19%54%
LMArena Math14491477
Omni-MATH55.3%—
MATH Level 597.7%—
FrontierMath (Feb 2025 set)15.2%—
FrontierMath Tier 4 (v1)4.2%—

Knowledge DeepSeek V4.1 Flash leads

Claude Sonnet 4.5: 48.4 (#76), DeepSeek V4.1 Flash: 57.9 (#38)

BenchmarkClaude Sonnet 4.5DeepSeek V4.1 Flash
GPQA Diamond82.3%89.8%
LMArena Expert14821506
Humanity's Last Exam13.7%—
SimpleQA Verified30.7%—
MMLU-Pro86.9%—
Vectara Hallucination Rate12%—
GPQA (HELM)68.6%—

Multimodal DeepSeek V4.1 Flash leads

Claude Sonnet 4.5: 34.8 (#89), DeepSeek V4.1 Flash: 39.1 (#61)

BenchmarkClaude Sonnet 4.5DeepSeek V4.1 Flash
LMArena Vision—1277
VPCT39.8%—
Furniture Assembly—34.2%
LMArena Document1450—

Multilingual DeepSeek V4.1 Flash leads

Claude Sonnet 4.5: 53.4 (#69), DeepSeek V4.1 Flash: 55.0 (#35)

BenchmarkClaude Sonnet 4.5DeepSeek V4.1 Flash
LMArena Non-English14251448
LMArena Chinese14591497
LMArena French14581452
LMArena German14271484
LMArena Japanese13901412
LMArena Korean14031452
LMArena Russian14371471
LMArena Spanish14571459

Instruction Following DeepSeek V4.1 Flash leads

Claude Sonnet 4.5: 75.0 (#78), DeepSeek V4.1 Flash: 77.3 (#26)

BenchmarkClaude Sonnet 4.5DeepSeek V4.1 Flash
LMArena Instruction Following14591474
IFEval85%—

Long Context Too close to call

Claude Sonnet 4.5: 45.2 (#46), DeepSeek V4.1 Flash: 45.2 (#47)

BenchmarkClaude Sonnet 4.5DeepSeek V4.1 Flash
LMArena Longer Query14761475

Writing & Preference Claude Sonnet 4.5 leads

Claude Sonnet 4.5: 66.5 (#34), DeepSeek V4.1 Flash: 65.4 (#48)

BenchmarkClaude Sonnet 4.5DeepSeek V4.1 Flash
LMArena Text14391462
LMArena Creative Writing14421435
EQ-Bench Creative Writing16781540
LMArena Multi-Turn14651457
WildBench85.4%—

Frequently asked questions

Is Claude Sonnet 4.5 better than DeepSeek V4.1 Flash?

DeepSeek V4.1 Flash is the stronger model overall, scoring 52.8 to 44.1 on the Noometry Index.

Which is cheaper, Claude Sonnet 4.5 or DeepSeek V4.1 Flash?

DeepSeek V4.1 Flash is cheaper. It lists at $0.15 per million input tokens and $0.60 per million output tokens; Claude Sonnet 4.5 lists at $3 and $15.

Is Claude Sonnet 4.5 or DeepSeek V4.1 Flash better for coding?

DeepSeek V4.1 Flash scores higher on coding benchmarks: 52.9 versus 47.3 in the Noometry coding category.

Which has the bigger context window?

DeepSeek V4.1 Flash does, with 1M tokens against 200K.

How many benchmarks do Claude Sonnet 4.5 and DeepSeek V4.1 Flash share?

32 benchmarks have published results for both models. Claude Sonnet 4.5 has 73 scored results on Noometry and DeepSeek V4.1 Flash has 37.

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