Noometry

Model comparison

GPT-5.3 Codex vs o1

GPT-5.3 Codex is the stronger model overall, scoring 45.8 to 40.9 on the Noometry Index.

Last verified . 3 shared benchmarks.

GPT-5.3 Codex OpenAI

45.8

Rank #69 Reported

o1 OpenAI

40.9

Rank #143 Confirmed

Summary

  • They share 3 benchmarks with published results for both. GPT-5.3 Codex scores higher in 2 categories and o1 in 0 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 24.6.
  • The biggest single-benchmark swing is WeirdML: 79.3% for GPT-5.3 Codex and 47.6% for o1.
  • GPT-5.3 Codex is cheaper at $1.75 / $14 per million input/output tokens, against $15 / $60 for o1.
  • GPT-5.3 Codex accepts more context: 400K tokens versus 200K.

Side by side

GPT-5.3 Codexo1
ProviderOpenAIOpenAI
Noometry Index45.840.9
Released2026-02-052024-09-12
WeightsProprietaryProprietary
Context window400K200K
Max output128K100K
Input $ / M tokens$1.75$15
Output $ / M tokens$14$60
Results tracked852

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Category by category

Coding GPT-5.3 Codex leads

GPT-5.3 Codex: 48.6 (#56), o1: 46.1 (#70)

BenchmarkGPT-5.3 Codexo1
WeirdML79.3%47.6%
SWE-bench Verified74.8%—
Aider Polyglot—61.7%
LMArena WebDev1409—
LiveBench Coding—69.7%
LMArena Coding—1367
CadEval—56%
ALE-Bench1,655—
HumanEval+—89%
MBPP+—80.2%

Agentic & Tool Use GPT-5.3 Codex leads

GPT-5.3 Codex: 48.0 (#9), o1: 24.6 (#117)

BenchmarkGPT-5.3 Codexo1
METR Time Horizons74.5%51.1%
Terminal-Bench78.4%—
Cybench—10%
Vending-Bench 25,940—

Reasoning Not comparable

GPT-5.3 Codex: —, o1: 27.9 (#111)

BenchmarkGPT-5.3 Codexo1
Epoch Capabilities Index156.77141.91
SimpleBench—41.7%
ARC-AGI-1—30.7%
Chess Puzzles—15%
EnigmaEval—5.7%
LiveBench Reasoning—91.6%
LMArena Hard Prompts—1371
DTBench—74.7%
LiveBench Data Analysis—65.5%
LMCA—22.3%
LiveBench—75.7%

Math Not comparable

GPT-5.3 Codex: —, o1: 36.1 (#175)

BenchmarkGPT-5.3 Codexo1
FrontierMath (Tiers 1-3)—14.7%
OTIS Mock AIME 2024-2025—73.3%
LiveBench Math—80.3%
LMArena Math—1388
MATH Level 5—94.7%
FrontierMath (Feb 2025 set)—9.3%

Knowledge Not comparable

GPT-5.3 Codex: —, o1: 41.5 (#110)

BenchmarkGPT-5.3 Codexo1
GPQA Diamond—76.8%
Humanity's Last Exam—8%
SimpleQA Verified—41.1%
Confabulations—11.7%
LMArena Expert—1361

Multimodal Not comparable

GPT-5.3 Codex: —, o1: 34.2 (#93)

BenchmarkGPT-5.3 Codexo1
LMArena Vision—1168
GeoBench—80%
VPCT—37%
SpatialViz-Bench—41.4%

Multilingual Not comparable

GPT-5.3 Codex: —, o1: 48.6 (#142)

BenchmarkGPT-5.3 Codexo1
LMArena Non-English—1358
LMArena Chinese—1394
LMArena French—1344
LMArena German—1337
LMArena Japanese—1346
LMArena Korean—1396
LMArena Russian—1356
LMArena Spanish—1345

Instruction Following Not comparable

GPT-5.3 Codex: —, o1: 74.8 (#86)

BenchmarkGPT-5.3 Codexo1
LiveBench Instruction Following—81.5%
LMArena Instruction Following—1367

Long Context Not comparable

GPT-5.3 Codex: —, o1: 50.3 (#9)

BenchmarkGPT-5.3 Codexo1
Fiction.LiveBench—83.3%
LMArena Longer Query—1378

Writing & Preference Not comparable

GPT-5.3 Codex: —, o1: 55.6 (#144)

BenchmarkGPT-5.3 Codexo1
LMArena Text—1366
LMArena Creative Writing—1348
Short-Story Creative Writing—70.2%
LMArena Multi-Turn—1369
LiveBench Language—65.4%

Frequently asked questions

Is GPT-5.3 Codex better than o1?

GPT-5.3 Codex is the stronger model overall, scoring 45.8 to 40.9 on the Noometry Index.

Which is cheaper, GPT-5.3 Codex or o1?

GPT-5.3 Codex is cheaper. It lists at $1.75 per million input tokens and $14 per million output tokens; o1 lists at $15 and $60.

Is GPT-5.3 Codex or o1 better for coding?

GPT-5.3 Codex scores higher on coding benchmarks: 48.6 versus 46.1 in the Noometry coding category.

Which has the bigger context window?

GPT-5.3 Codex does, with 400K tokens against 200K.

How many benchmarks do GPT-5.3 Codex and o1 share?

3 benchmarks have published results for both models. GPT-5.3 Codex has 8 scored results on Noometry and o1 has 52.

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