Noometry

Model comparison

Claude Sonnet 5 vs GPT-5.3 Codex

Claude Sonnet 5 is the stronger model overall, scoring 54.6 to 45.8 on the Noometry Index.

Last verified . 5 shared benchmarks.

Claude Sonnet 5 Anthropic

54.6

Rank #29 Confirmed

GPT-5.3 Codex OpenAI

45.8

Rank #69 Reported

Summary

  • They share 5 benchmarks with published results for both. Claude Sonnet 5 scores higher in 1 category and GPT-5.3 Codex in 1 category; 2 gaps are clear of the uncertainty.
  • The widest gap is in coding, where Claude Sonnet 5 leads 55.5 to 48.6.
  • The biggest single-benchmark swing is WeirdML: 68.8% for Claude Sonnet 5 and 79.3% for GPT-5.3 Codex.
  • Claude Sonnet 5 is cheaper at $2 / $10 per million input/output tokens, against $1.75 / $14 for GPT-5.3 Codex.
  • Claude Sonnet 5 accepts more context: 1M tokens versus 400K.

Side by side

Claude Sonnet 5GPT-5.3 Codex
ProviderAnthropicOpenAI
Noometry Index54.645.8
Released2026-06-292026-02-05
WeightsProprietaryProprietary
Context window1M400K
Max output128K128K
Input $ / M tokens$2$1.75
Output $ / M tokens$10$14
Results tracked518

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Category by category

Coding Claude Sonnet 5 leads

Claude Sonnet 5: 55.5 (#26), GPT-5.3 Codex: 48.6 (#56)

BenchmarkClaude Sonnet 5GPT-5.3 Codex
LMArena WebDev15411409
WeirdML68.8%79.3%
ALE-Bench1,4631,655
SWE-bench Verified—74.8%
DeepSWE53.8%—
FrontierCode42.7%—
CursorBench34.1%—
SciCode54.3%—
GSO37.3%—
LMArena Coding1483—

Agentic & Tool Use GPT-5.3 Codex leads

Claude Sonnet 5: 42.8 (#18), GPT-5.3 Codex: 48.0 (#9)

BenchmarkClaude Sonnet 5GPT-5.3 Codex
Vending-Bench 26,3785,940
Terminal-Bench—78.4%
APEX-Agents54.5%—
GBAEval65.3%—
LMArena Search1194—
METR Time Horizons—74.5%

Reasoning Not comparable

Claude Sonnet 5: 49.1 (#39), GPT-5.3 Codex: —

BenchmarkClaude Sonnet 5GPT-5.3 Codex
Epoch Capabilities Index156.21156.77
SimpleBench60.6%—
NYT Connections (extended)75.1%—
CritPt16.9%—
Chess Puzzles35%—
LMArena Hard Prompts1461—
Mystery Game Puzzles35%—
DTBench92.5%—
LMCA50%—
Surface Evolver Bench60%—
Bench to the Future 30.14—
ForecastBench61.1—

Math Not comparable

Claude Sonnet 5: 66.2 (#27), GPT-5.3 Codex: —

BenchmarkClaude Sonnet 5GPT-5.3 Codex
FrontierMath (Tiers 1-3)65.6%—
FrontierMath Tier 429.3%—
OTIS Mock AIME 2024-202594.7%—
ProofBench77%—
LMArena Math1467—

Knowledge Not comparable

Claude Sonnet 5: 55.6 (#47), GPT-5.3 Codex: —

BenchmarkClaude Sonnet 5GPT-5.3 Codex
GPQA Diamond90.5%—
SimpleQA Verified33.7%—
LMArena Expert1490—

Multimodal Not comparable

Claude Sonnet 5: 42.4 (#31), GPT-5.3 Codex: —

BenchmarkClaude Sonnet 5GPT-5.3 Codex
LMArena Vision1274—
Blueprint-Bench 224.9%—
LMArena Document1466—

Multilingual Not comparable

Claude Sonnet 5: 53.8 (#55), GPT-5.3 Codex: —

BenchmarkClaude Sonnet 5GPT-5.3 Codex
LMArena Non-English1431—
LMArena Chinese1477—
LMArena French1460—
LMArena German1440—
LMArena Japanese1422—
LMArena Korean1411—
LMArena Russian1451—
LMArena Spanish1437—

Instruction Following Not comparable

Claude Sonnet 5: 76.3 (#41), GPT-5.3 Codex: —

BenchmarkClaude Sonnet 5GPT-5.3 Codex
LMArena Instruction Following1452—

Long Context Not comparable

Claude Sonnet 5: 44.8 (#55), GPT-5.3 Codex: —

BenchmarkClaude Sonnet 5GPT-5.3 Codex
LMArena Longer Query1463—

Writing & Preference Not comparable

Claude Sonnet 5: 69.2 (#25), GPT-5.3 Codex: —

BenchmarkClaude Sonnet 5GPT-5.3 Codex
LMArena Text1442—
LMArena Creative Writing1416—
EQ-Bench Creative Writing1794—
EQ-Bench 41236—
LMArena Multi-Turn1454—

Frequently asked questions

Is Claude Sonnet 5 better than GPT-5.3 Codex?

Claude Sonnet 5 is the stronger model overall, scoring 54.6 to 45.8 on the Noometry Index.

Which is cheaper, Claude Sonnet 5 or GPT-5.3 Codex?

Claude Sonnet 5 is cheaper. It lists at $2 per million input tokens and $10 per million output tokens; GPT-5.3 Codex lists at $1.75 and $14.

Is Claude Sonnet 5 or GPT-5.3 Codex better for coding?

Claude Sonnet 5 scores higher on coding benchmarks: 55.5 versus 48.6 in the Noometry coding category.

Which has the bigger context window?

Claude Sonnet 5 does, with 1M tokens against 400K.

How many benchmarks do Claude Sonnet 5 and GPT-5.3 Codex share?

5 benchmarks have published results for both models. Claude Sonnet 5 has 51 scored results on Noometry and GPT-5.3 Codex has 8.

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