Noometry

Model comparison

Claude Sonnet 5 vs GPT-5.5 Instant

Claude Sonnet 5 is the stronger model overall, scoring 54.6 to 42.7 on the Noometry Index.

Last verified . 27 shared benchmarks.

Claude Sonnet 5 Anthropic

54.6

Rank #29 Confirmed

GPT-5.5 Instant OpenAI

42.7

Rank #110 Confirmed

Summary

  • They share 27 benchmarks with published results for both. Claude Sonnet 5 scores higher in 9 categories and GPT-5.5 Instant in 0 categories; 9 gaps are clear of the uncertainty.
  • The widest gap is in math, where Claude Sonnet 5 leads 66.2 to 26.5.
  • The biggest single-benchmark swing is FrontierMath (Tiers 1-3): 65.6% for Claude Sonnet 5 and 26.3% for GPT-5.5 Instant.

Side by side

Claude Sonnet 5GPT-5.5 Instant
ProviderAnthropicOpenAI
Noometry Index54.642.7
Released2026-06-292026-05-05
WeightsProprietaryProprietary
Context window1M—
Max output128K—
Input $ / M tokens$2—
Output $ / M tokens$10—
Results tracked5127

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Category by category

Coding Claude Sonnet 5 leads

Claude Sonnet 5: 55.5 (#26), GPT-5.5 Instant: 44.3 (#74)

BenchmarkClaude Sonnet 5GPT-5.5 Instant
SciCode54.3%48.6%
LMArena Coding14831433
DeepSWE53.8%—
FrontierCode42.7%—
CursorBench34.1%—
LMArena WebDev1541—
GSO37.3%—
WeirdML68.8%—
ALE-Bench1,463—

Agentic & Tool Use Not comparable

Claude Sonnet 5: 42.8 (#18), GPT-5.5 Instant: —

BenchmarkClaude Sonnet 5GPT-5.5 Instant
APEX-Agents54.5%—
GBAEval65.3%—
LMArena Search1194—
Vending-Bench 26,378—

Reasoning Claude Sonnet 5 leads

Claude Sonnet 5: 49.1 (#39), GPT-5.5 Instant: 24.9 (#155)

BenchmarkClaude Sonnet 5GPT-5.5 Instant
CritPt16.9%0%
Chess Puzzles35%12%
LMArena Hard Prompts14611426
Epoch Capabilities Index156.21142.52
SimpleBench60.6%—
NYT Connections (extended)75.1%—
Mystery Game Puzzles35%—
DTBench92.5%—
LMCA50%—
Surface Evolver Bench60%—
Bench to the Future 30.14—
ForecastBench61.1—

Math Claude Sonnet 5 leads

Claude Sonnet 5: 66.2 (#27), GPT-5.5 Instant: 26.5 (#259)

BenchmarkClaude Sonnet 5GPT-5.5 Instant
FrontierMath (Tiers 1-3)65.6%26.3%
FrontierMath Tier 429.3%2.4%
OTIS Mock AIME 2024-202594.7%68.1%
LMArena Math14671420
ProofBench77%—

Knowledge Claude Sonnet 5 leads

Claude Sonnet 5: 55.6 (#47), GPT-5.5 Instant: 48.9 (#74)

BenchmarkClaude Sonnet 5GPT-5.5 Instant
GPQA Diamond90.5%82.5%
LMArena Expert14901409
SimpleQA Verified33.7%—

Multimodal Claude Sonnet 5 leads

Claude Sonnet 5: 42.4 (#31), GPT-5.5 Instant: 40.0 (#52)

BenchmarkClaude Sonnet 5GPT-5.5 Instant
LMArena Vision12741250
LMArena Document14661403
Blueprint-Bench 224.9%—

Multilingual Claude Sonnet 5 leads

Claude Sonnet 5: 53.8 (#55), GPT-5.5 Instant: 52.8 (#80)

BenchmarkClaude Sonnet 5GPT-5.5 Instant
LMArena Non-English14311417
LMArena Chinese14771456
LMArena French14601428
LMArena German14401411
LMArena Japanese14221408
LMArena Korean14111392
LMArena Russian14511431
LMArena Spanish14371429

Instruction Following Claude Sonnet 5 leads

Claude Sonnet 5: 76.3 (#41), GPT-5.5 Instant: 74.2 (#100)

BenchmarkClaude Sonnet 5GPT-5.5 Instant
LMArena Instruction Following14521406

Long Context Claude Sonnet 5 leads

Claude Sonnet 5: 44.8 (#55), GPT-5.5 Instant: 43.4 (#96)

BenchmarkClaude Sonnet 5GPT-5.5 Instant
LMArena Longer Query14631422

Writing & Preference Claude Sonnet 5 leads

Claude Sonnet 5: 69.2 (#25), GPT-5.5 Instant: 61.8 (#85)

BenchmarkClaude Sonnet 5GPT-5.5 Instant
LMArena Text14421419
LMArena Creative Writing14161419
LMArena Multi-Turn14541433
EQ-Bench Creative Writing1794—
EQ-Bench 41236—

Frequently asked questions

Is Claude Sonnet 5 better than GPT-5.5 Instant?

Claude Sonnet 5 is the stronger model overall, scoring 54.6 to 42.7 on the Noometry Index.

Is Claude Sonnet 5 or GPT-5.5 Instant better for coding?

Claude Sonnet 5 scores higher on coding benchmarks: 55.5 versus 44.3 in the Noometry coding category.

How many benchmarks do Claude Sonnet 5 and GPT-5.5 Instant share?

27 benchmarks have published results for both models. Claude Sonnet 5 has 51 scored results on Noometry and GPT-5.5 Instant has 27.

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