Noometry

Model comparison

Claude Sonnet 5.5 vs o3-pro

Claude Sonnet 5.5 is the stronger model overall, scoring 61.9 to 42.9 on the Noometry Index.

Last verified . 1 shared benchmarks.

Claude Sonnet 5.5 Anthropic

61.9

Rank #10 Confirmed

o3-pro OpenAI

42.9

Rank #105 Confirmed

Summary

  • They share 1 benchmark with published results for both. Claude Sonnet 5.5 scores higher in 4 categories and o3-pro in 1 category; 5 gaps are clear of the uncertainty.
  • The widest gap is in knowledge, where Claude Sonnet 5.5 leads 66.0 to 29.5.
  • Claude Sonnet 5.5 is cheaper at $2 / $10 per million input/output tokens, against $20 / $80 for o3-pro.
  • Claude Sonnet 5.5 accepts more context: 1M tokens versus 200K.

Side by side

Claude Sonnet 5.5o3-pro
ProviderAnthropicOpenAI
Noometry Index61.942.9
Released2026-09-282025-06-10
WeightsProprietaryProprietary
Context window1M200K
Max output128K100K
Input $ / M tokens$2$20
Output $ / M tokens$10$80
Results tracked3212

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Category by category

Coding Claude Sonnet 5.5 leads

Claude Sonnet 5.5: 67.3 (#6), o3-pro: 55.5 (#24)

BenchmarkClaude Sonnet 5.5o3-pro
FrontierCode52.1%—
Aider Polyglot—84.9%
CursorBench55.5%—
LMArena WebDev1774—
FrontierSWE61.9%—
SciCode61%—
WeirdML—58.2%
LMArena Coding1513—
ALE-Bench1,819—

Agentic & Tool Use Not comparable

Claude Sonnet 5.5: 45.0 (#16), o3-pro: —

BenchmarkClaude Sonnet 5.5o3-pro
APEX-Agents75.5%—

Reasoning Claude Sonnet 5.5 leads

Claude Sonnet 5.5: 54.0 (#28), o3-pro: 23.8 (#171)

BenchmarkClaude Sonnet 5.5o3-pro
Epoch Capabilities Index165.03147.42
ARC-AGI-2—4.9%
Kagi LLM Benchmark—72.1%
NYT Connections (extended)80.5%—
ARC-AGI-1—59.3%
CritPt31.4%—
LMArena Hard Prompts1495—
Mystery Game Puzzles65%—
DTBench—86.9%
LMCA—38.5%

Math Not comparable

Claude Sonnet 5.5: 87.9 (#6), o3-pro: —

BenchmarkClaude Sonnet 5.5o3-pro
FrontierMath (Tiers 1-3)88.8%—
FrontierMath Tier 480.5%—
OTIS Mock AIME 2024-2025100%—
ProofBench100%—
LMArena Math1510—
FrontierMath Erdős2.9%—

Knowledge Claude Sonnet 5.5 leads

Claude Sonnet 5.5: 66.0 (#12), o3-pro: 29.5 (#238)

BenchmarkClaude Sonnet 5.5o3-pro
GPQA Diamond95.6%—
SimpleQA Verified46.5%—
Confabulations—14.2%
Vectara Hallucination Rate—23.3%
LMArena Expert1540—

Multimodal Not comparable

Claude Sonnet 5.5: 51.5 (#6), o3-pro: —

BenchmarkClaude Sonnet 5.5o3-pro
LMArena Vision1289—
Furniture Assembly75%—

Multilingual Not comparable

Claude Sonnet 5.5: 55.3 (#30), o3-pro: —

BenchmarkClaude Sonnet 5.5o3-pro
LMArena Non-English1452—
LMArena Chinese1522—
LMArena Russian1451—

Instruction Following Not comparable

Claude Sonnet 5.5: 78.3 (#11), o3-pro: —

BenchmarkClaude Sonnet 5.5o3-pro
LMArena Instruction Following1495—

Long Context o3-pro leads

Claude Sonnet 5.5: 45.9 (#28), o3-pro: 72.2 (#1)

BenchmarkClaude Sonnet 5.5o3-pro
Fiction.LiveBench—97.2%
LMArena Longer Query1498—

Writing & Preference Claude Sonnet 5.5 leads

Claude Sonnet 5.5: 66.0 (#40), o3-pro: 57.1 (#133)

BenchmarkClaude Sonnet 5.5o3-pro
LMArena Text1471—
LMArena Creative Writing1465—
Short-Story Creative Writing—84.4%
LMArena Multi-Turn1474—

Frequently asked questions

Is Claude Sonnet 5.5 better than o3-pro?

Claude Sonnet 5.5 is the stronger model overall, scoring 61.9 to 42.9 on the Noometry Index.

Which is cheaper, Claude Sonnet 5.5 or o3-pro?

Claude Sonnet 5.5 is cheaper. It lists at $2 per million input tokens and $10 per million output tokens; o3-pro lists at $20 and $80.

Is Claude Sonnet 5.5 or o3-pro better for coding?

Claude Sonnet 5.5 scores higher on coding benchmarks: 67.3 versus 55.5 in the Noometry coding category.

Which has the bigger context window?

Claude Sonnet 5.5 does, with 1M tokens against 200K.

How many benchmarks do Claude Sonnet 5.5 and o3-pro share?

1 benchmark has published results for both models. Claude Sonnet 5.5 has 32 scored results on Noometry and o3-pro has 12.

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