Model comparison

Claude 3.5 Haiku vs GPT-5.3 Codex

GPT-5.3 Codex is the stronger model overall, scoring 45.8 to 29.2 on the Noometry Index.

Last verified . 2 shared benchmarks.

Claude 3.5 Haiku Anthropic

29.2

Rank #315 Confirmed

GPT-5.3 Codex OpenAI

45.8

Rank #69 Reported

Summary

  • They share 2 benchmarks with published results for both. Claude 3.5 Haiku scores higher in 0 categories and GPT-5.3 Codex in 2 categories; 2 gaps are clear of the uncertainty.
  • The widest gap is in agentic & tool use, where GPT-5.3 Codex leads 48.0 to 28.0.
  • The biggest single-benchmark swing is WeirdML: 30.7% for Claude 3.5 Haiku and 79.3% for GPT-5.3 Codex.

Side by side

Claude 3.5 Haiku and GPT-5.3 Codex specifications
Claude 3.5 HaikuGPT-5.3 Codex
ProviderAnthropicOpenAI
Noometry Index29.245.8
Released2024-10-222026-02-05
WeightsProprietaryProprietary
Context window—400K
Max output—128K
Input $ / M tokens—$1.75
Output $ / M tokens—$14
Results tracked498

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Category by category

Coding GPT-5.3 Codex leads

Claude 3.5 Haiku: 32.9 (#265), GPT-5.3 Codex: 48.6 (#56)

Coding benchmarks
BenchmarkClaude 3.5 HaikuGPT-5.3 Codex
WeirdML30.7%79.3%
SWE-bench Verified—74.8%
Aider Polyglot28%—
LMArena WebDev—1409
SciCode27.4%—
BigCodeBench Instruct46.1%—
LiveBench Coding51.4%—
LMArena Coding1286—
BigCodeBench Complete59%—
CadEval32%—
ALE-Bench—1,655

Agentic & Tool Use GPT-5.3 Codex leads

Claude 3.5 Haiku: 28.0 (#95), GPT-5.3 Codex: 48.0 (#9)

Agentic & Tool Use benchmarks
BenchmarkClaude 3.5 HaikuGPT-5.3 Codex
Terminal-Bench—78.4%
BALROG19.3%—
METR Time Horizons—74.5%
Vending-Bench 2—5,940

Reasoning Not comparable

Claude 3.5 Haiku: 17.7 (#290), GPT-5.3 Codex: —

Reasoning benchmarks
BenchmarkClaude 3.5 HaikuGPT-5.3 Codex
Epoch Capabilities Index127.15156.77
CritPt0%—
LiveBench Reasoning28.1%—
LMArena Hard Prompts1251—
DTBench56.7%—
LiveBench Data Analysis48.5%—
LiveBench43.5%—

Math Not comparable

Claude 3.5 Haiku: 14.7 (#300), GPT-5.3 Codex: —

Math benchmarks
BenchmarkClaude 3.5 HaikuGPT-5.3 Codex
OTIS Mock AIME 2024-20254.3%—
Omni-MATH22.4%—
LiveBench Math35.5%—
LMArena Math1244—
MATH Level 546.4%—
FrontierMath (Feb 2025 set)0.3%—

Knowledge Not comparable

Claude 3.5 Haiku: 18.7 (#281), GPT-5.3 Codex: —

Knowledge benchmarks
BenchmarkClaude 3.5 HaikuGPT-5.3 Codex
GPQA Diamond38.1%—
MMLU-Pro60.5%—
Confabulations36.7%—
GPQA (HELM)36.3%—
LMArena Expert1208—
MMLU74.3%—

Multimodal Not comparable

Claude 3.5 Haiku: 26.8 (#117), GPT-5.3 Codex: —

Multimodal benchmarks
BenchmarkClaude 3.5 HaikuGPT-5.3 Codex
LMArena Vision1092—
GeoBench34%—

Multilingual Not comparable

Claude 3.5 Haiku: 40.0 (#218), GPT-5.3 Codex: —

Multilingual benchmarks
BenchmarkClaude 3.5 HaikuGPT-5.3 Codex
LMArena Non-English1238—
LMArena Chinese1229—
LMArena French1264—
LMArena German1237—
LMArena Japanese1175—
LMArena Korean1173—
LMArena Russian1253—
LMArena Spanish1261—

Instruction Following Not comparable

Claude 3.5 Haiku: 62.9 (#234), GPT-5.3 Codex: —

Instruction Following benchmarks
BenchmarkClaude 3.5 HaikuGPT-5.3 Codex
LiveBench Instruction Following61.9%—
IFEval79.2%—
LMArena Instruction Following1241—

Long Context Not comparable

Claude 3.5 Haiku: 38.3 (#200), GPT-5.3 Codex: —

Long Context benchmarks
BenchmarkClaude 3.5 HaikuGPT-5.3 Codex
LMArena Longer Query1261—

Writing & Preference Not comparable

Claude 3.5 Haiku: 42.7 (#234), GPT-5.3 Codex: —

Writing & Preference benchmarks
BenchmarkClaude 3.5 HaikuGPT-5.3 Codex
LMArena Text1255—
LMArena Creative Writing1233—
Short-Story Creative Writing73.5%—
EQ-Bench Creative Writing1146—
WildBench76%—
LMArena Multi-Turn1265—
LiveBench Language35.4%—

Frequently asked questions

Is Claude 3.5 Haiku better than GPT-5.3 Codex?

GPT-5.3 Codex is the stronger model overall, scoring 45.8 to 29.2 on the Noometry Index.

Is Claude 3.5 Haiku or GPT-5.3 Codex better for coding?

GPT-5.3 Codex scores higher on coding benchmarks: 48.6 versus 32.9 in the Noometry coding category.

How many benchmarks do Claude 3.5 Haiku and GPT-5.3 Codex share?

2 benchmarks have published results for both models. Claude 3.5 Haiku has 49 scored results on Noometry and GPT-5.3 Codex has 8.

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