Noometry

Model comparison

Claude Sonnet 4.5 vs DeepSeek-V3.1

Claude Sonnet 4.5 is the stronger model overall, scoring 44.1 to 42.8 on the Noometry Index. DeepSeek-V3.1 costs 14× less per token, which makes it the better buy when Claude Sonnet 4.5's lead doesn't matter for your workload.

Last verified . 26 shared benchmarks.

Claude Sonnet 4.5 Anthropic

44.1

Rank #81 Confirmed

DeepSeek-V3.1 DeepSeek

42.8

Rank #108 Confirmed

Summary

  • They share 26 benchmarks with published results for both. Claude Sonnet 4.5 scores higher in 6 categories and DeepSeek-V3.1 in 2 categories; 7 gaps are clear of the uncertainty.
  • The widest gap is in long context, where Claude Sonnet 4.5 leads 45.2 to 36.3.
  • The biggest single-benchmark swing is LMCA: 38.8% for Claude Sonnet 4.5 and 24.3% for DeepSeek-V3.1.
  • DeepSeek-V3.1 is cheaper at $0.25 / $0.95 per million input/output tokens, against $3 / $15 for Claude Sonnet 4.5.
  • Claude Sonnet 4.5 accepts more context: 200K tokens versus 164K.
  • DeepSeek-V3.1 has downloadable open weights; the other is API-only.

Side by side

Claude Sonnet 4.5DeepSeek-V3.1
ProviderAnthropicDeepSeek
Noometry Index44.142.8
Released2025-09-292025-08-21
WeightsProprietaryOpen
Context window200K164K
Max output64K8K
Input $ / M tokens$3$0.25
Output $ / M tokens$15$0.95
Results tracked7327

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Category by category

Coding Claude Sonnet 4.5 leads

Claude Sonnet 4.5: 47.3 (#61), DeepSeek-V3.1: 40.3 (#144)

BenchmarkClaude Sonnet 4.5DeepSeek-V3.1
WeirdML47.7%38.4%
LMArena Coding14891417
SWE-bench Verified71.3%—
SWE-bench Verified (bash only)71.4%—
LMArena WebDev1393—
SWE-bench Multilingual67%—
SciCode44.7%—
GSO14.7%—
ALE-Bench796.15—
AlgoTune1.52—

Agentic & Tool Use Not comparable

Claude Sonnet 4.5: 38.3 (#32), DeepSeek-V3.1: —

BenchmarkClaude Sonnet 4.5DeepSeek-V3.1
Terminal-Bench46.5%—
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%—
LMArena Search1159—
METR Time Horizons67.4%—
Vending-Bench 23,839—

Reasoning Too close to call

Claude Sonnet 4.5: 26.9 (#125), DeepSeek-V3.1: 27.9 (#110)

BenchmarkClaude Sonnet 4.5DeepSeek-V3.1
SimpleBench54.3%40%
Kagi LLM Benchmark57.9%53.2%
LMArena Hard Prompts14621417
DTBench83.2%82.7%
LMCA38.8%24.3%
Epoch Capabilities Index146.84139.92
ForecastBench61.958
ARC-AGI-213.6%—
NYT Connections (extended)37.3%—
ARC-AGI-163.7%—
CritPt1.1%—
Chess Puzzles12%—
EnigmaEval6%—
EBR-Bench2.4%—
Mystery Game Puzzles17%—

Math DeepSeek-V3.1 leads

Claude Sonnet 4.5: 32.3 (#216), DeepSeek-V3.1: 38.9 (#122)

BenchmarkClaude Sonnet 4.5DeepSeek-V3.1
LMArena Math14491420
FrontierMath (Tiers 1-3)23.9%—
FrontierMath Tier 42.4%—
OTIS Mock AIME 2024-202577.8%—
ProofBench19%—
Omni-MATH55.3%—
MATH Level 597.7%—
FrontierMath (Feb 2025 set)15.2%—
FrontierMath Tier 4 (v1)4.2%—

Knowledge Claude Sonnet 4.5 leads

Claude Sonnet 4.5: 48.4 (#76), DeepSeek-V3.1: 43.7 (#90)

BenchmarkClaude Sonnet 4.5DeepSeek-V3.1
Vectara Hallucination Rate12%5.5%
LMArena Expert14821405
GPQA Diamond82.3%—
Humanity's Last Exam13.7%—
SimpleQA Verified30.7%—
MMLU-Pro86.9%—
GPQA (HELM)68.6%—

Multimodal Not comparable

Claude Sonnet 4.5: 34.8 (#89), DeepSeek-V3.1: —

BenchmarkClaude Sonnet 4.5DeepSeek-V3.1
VPCT39.8%—
LMArena Document1450—

Multilingual Claude Sonnet 4.5 leads

Claude Sonnet 4.5: 53.4 (#69), DeepSeek-V3.1: 51.6 (#106)

BenchmarkClaude Sonnet 4.5DeepSeek-V3.1
LMArena Non-English14251400
LMArena Chinese14591469
LMArena French14581447
LMArena German14271411
LMArena Japanese13901378
LMArena Korean14031337
LMArena Russian14371405
LMArena Spanish14571431

Instruction Following Claude Sonnet 4.5 leads

Claude Sonnet 4.5: 75.0 (#78), DeepSeek-V3.1: 73.9 (#110)

BenchmarkClaude Sonnet 4.5DeepSeek-V3.1
LMArena Instruction Following14591400
IFEval85%—

Long Context Claude Sonnet 4.5 leads

Claude Sonnet 4.5: 45.2 (#46), DeepSeek-V3.1: 36.3 (#232)

BenchmarkClaude Sonnet 4.5DeepSeek-V3.1
LMArena Longer Query14761422
Fiction.LiveBench—52.8%

Writing & Preference Claude Sonnet 4.5 leads

Claude Sonnet 4.5: 66.5 (#34), DeepSeek-V3.1: 60.3 (#98)

BenchmarkClaude Sonnet 4.5DeepSeek-V3.1
LMArena Text14391420
LMArena Creative Writing14421401
EQ-Bench Creative Writing16781436
LMArena Multi-Turn14651408
WildBench85.4%—

Frequently asked questions

Is Claude Sonnet 4.5 better than DeepSeek-V3.1?

Claude Sonnet 4.5 is the stronger model overall, scoring 44.1 to 42.8 on the Noometry Index. DeepSeek-V3.1 costs 14× less per token, which makes it the better buy when Claude Sonnet 4.5's lead doesn't matter for your workload.

Which is cheaper, Claude Sonnet 4.5 or DeepSeek-V3.1?

DeepSeek-V3.1 is cheaper. It lists at $0.25 per million input tokens and $0.95 per million output tokens; Claude Sonnet 4.5 lists at $3 and $15.

Is Claude Sonnet 4.5 or DeepSeek-V3.1 better for coding?

Claude Sonnet 4.5 scores higher on coding benchmarks: 47.3 versus 40.3 in the Noometry coding category.

Which has the bigger context window?

Claude Sonnet 4.5 does, with 200K tokens against 164K.

How many benchmarks do Claude Sonnet 4.5 and DeepSeek-V3.1 share?

26 benchmarks have published results for both models. Claude Sonnet 4.5 has 73 scored results on Noometry and DeepSeek-V3.1 has 27.

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