Model comparison

Claude Opus 4 vs Claude Sonnet 4.5

Claude Sonnet 4.5 is the stronger model overall, scoring 44.0 to 42.9 on the Noometry Index.

Last verified . 50 shared benchmarks.

Claude Opus 4 Anthropic

42.9

Rank #93 Confirmed

Claude Sonnet 4.5 Anthropic

44.0

Rank #76 Confirmed

Summary

  • They share 50 benchmarks with published results for both. Claude Opus 4 scores higher in 3 categories and Claude Sonnet 4.5 in 7 categories; 8 gaps are clear of the uncertainty.
  • The widest gap is in math, where Claude Opus 4 leads 40.2 to 31.9.
  • The biggest single-benchmark swing is ARC-AGI-1: 35.7% for Claude Opus 4 and 63.7% for Claude Sonnet 4.5.
  • Claude Sonnet 4.5 is cheaper at $3 / $15 per million input/output tokens, against $15 / $75 for Claude Opus 4.
  • Claude Sonnet 4.5 accepts more context: 1M tokens versus 200K.

Side by side

Claude Opus 4 and Claude Sonnet 4.5 specifications
Claude Opus 4Claude Sonnet 4.5
ProviderAnthropicAnthropic
Noometry Index42.944.0
Released2025-05-222025-09-29
WeightsProprietaryProprietary
Context window200K1M
Max output32K64K
Input $ / M tokens$15$3
Output $ / M tokens$75$15
Results tracked5673

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Category by category

Coding Too close to call

Claude Opus 4: 47.8 (#55), Claude Sonnet 4.5: 47.8 (#54)

Coding benchmarks
BenchmarkClaude Opus 4Claude Sonnet 4.5
SWE-bench Verified70.7%71.3%
SWE-bench Verified (bash only)67.6%71.4%
GSO6.9%14.7%
WeirdML43.7%47.7%
LMArena Coding14421489
AlgoTune1.331.52
Aider Polyglot72%—
LMArena WebDev—1393
SWE-bench Multilingual—67%
SciCode—44.7%
ALE-Bench—796.15

Agentic & Tool Use Claude Sonnet 4.5 leads

Claude Opus 4: 34.5 (#39), Claude Sonnet 4.5: 38.1 (#30)

Agentic & Tool Use benchmarks
BenchmarkClaude Opus 4Claude Sonnet 4.5
Cybench38%60%
DeepResearch Bench46.8%52.6%
LMArena Search11271159
METR Time Horizons63.9%67.4%
Terminal-Bench—46.5%
Berkeley Function Calling Leaderboard—73.2%
GDPval—42.5%
Remote Labor Index—2.1%
τ²-bench Airline—72%
τ²-bench Banking—25.3%
τ²-bench Retail—72.4%
τ²-bench Telecom—84.9%
OSWorld—62.9%
Vending-Bench 2—3,839

Reasoning Too close to call

Claude Opus 4: 27.4 (#104), Claude Sonnet 4.5: 26.9 (#113)

Reasoning benchmarks
BenchmarkClaude Opus 4Claude Sonnet 4.5
ARC-AGI-28.6%13.6%
SimpleBench58.8%54.3%
Kagi LLM Benchmark74.3%57.9%
ARC-AGI-135.7%63.7%
CritPt0.3%1.1%
EnigmaEval5.6%6%
LMArena Hard Prompts13991462
DTBench81.6%83.2%
LMCA37.4%38.8%
Epoch Capabilities Index142.67146.84
ForecastBench61.161.9
NYT Connections (extended)—37.3%
Chess Puzzles—12%
EBR-Bench—2.4%
Mystery Game Puzzles—17%

Math Claude Opus 4 leads

Claude Opus 4: 40.2 (#80), Claude Sonnet 4.5: 31.9 (#190)

Math benchmarks
BenchmarkClaude Opus 4Claude Sonnet 4.5
OTIS Mock AIME 2024-202564.4%77.8%
Omni-MATH61.6%55.3%
LMArena Math13911448
MATH Level 585%97.7%
FrontierMath (Feb 2025 set)4.5%15.2%
FrontierMath Tier 4 (v1)4.2%4.2%
FrontierMath (Tiers 1-3)—23.9%
FrontierMath Tier 4—2.4%
ProofBench—19%

Knowledge Claude Sonnet 4.5 leads

Claude Opus 4: 43.9 (#82), Claude Sonnet 4.5: 48.4 (#70)

Knowledge benchmarks
BenchmarkClaude Opus 4Claude Sonnet 4.5
GPQA Diamond76.3%82.3%
Humanity's Last Exam10.7%13.7%
MMLU-Pro87.5%86.9%
Vectara Hallucination Rate12%12%
GPQA (HELM)70.8%68.6%
LMArena Expert13841483
SimpleQA Verified—30.7%
Confabulations15.9%—

Multimodal Claude Sonnet 4.5 leads

Claude Opus 4: 30.9 (#101), Claude Sonnet 4.5: 34.1 (#84)

Multimodal benchmarks
BenchmarkClaude Opus 4Claude Sonnet 4.5
VPCT38%39.8%
LMArena Vision1192—
GeoBench49%—
LMArena Document—1450

Multilingual Claude Sonnet 4.5 leads

Claude Opus 4: 49.0 (#133), Claude Sonnet 4.5: 53.6 (#65)

Multilingual benchmarks
BenchmarkClaude Opus 4Claude Sonnet 4.5
LMArena Non-English13621425
LMArena Chinese13861459
LMArena French13701459
LMArena German13911427
LMArena Japanese13321390
LMArena Korean13181403
LMArena Russian13921436
LMArena Spanish13881457

Instruction Following Claude Opus 4 leads

Claude Opus 4: 77.3 (#26), Claude Sonnet 4.5: 75.2 (#74)

Instruction Following benchmarks
BenchmarkClaude Opus 4Claude Sonnet 4.5
IFEval91.8%85%
LMArena Instruction Following14061459

Long Context Claude Sonnet 4.5 leads

Claude Opus 4: 39.5 (#167), Claude Sonnet 4.5: 45.2 (#45)

Long Context benchmarks
BenchmarkClaude Opus 4Claude Sonnet 4.5
LMArena Longer Query14221476
Fiction.LiveBench61.1%—

Writing & Preference Claude Sonnet 4.5 leads

Claude Opus 4: 61.4 (#85), Claude Sonnet 4.5: 66.7 (#33)

Writing & Preference benchmarks
BenchmarkClaude Opus 4Claude Sonnet 4.5
LMArena Text13771439
LMArena Creative Writing13861442
EQ-Bench Creative Writing15801678
WildBench85.2%85.4%
LMArena Multi-Turn13961465
Short-Story Creative Writing83.6%—

Frequently asked questions

Is Claude Opus 4 better than Claude Sonnet 4.5?

Claude Sonnet 4.5 is the stronger model overall, scoring 44.0 to 42.9 on the Noometry Index.

Which is cheaper, Claude Opus 4 or Claude Sonnet 4.5?

Claude Sonnet 4.5 is cheaper. It lists at $3 per million input tokens and $15 per million output tokens; Claude Opus 4 lists at $15 and $75.

Is Claude Opus 4 or Claude Sonnet 4.5 better for coding?

They score almost the same on coding (47.8 vs 47.8); test both on your own repository before choosing.

Which has the bigger context window?

Claude Sonnet 4.5 does, with 1M tokens against 200K.

How many benchmarks do Claude Opus 4 and Claude Sonnet 4.5 share?

50 benchmarks have published results for both models. Claude Opus 4 has 56 scored results on Noometry and Claude Sonnet 4.5 has 73.

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