Model comparison

GPT-5 vs GPT-5.2 Codex

GPT-5 is the stronger model overall, scoring 50.9 to 42.6 on the Noometry Index.

Last verified . 4 shared benchmarks.

GPT-5 OpenAI

50.9

Rank #45 Confirmed

GPT-5.2 Codex OpenAI

42.6

Rank #111 Reported

Summary

  • They share 4 benchmarks with published results for both. GPT-5 scores higher in 1 category and GPT-5.2 Codex in 1 category; 2 gaps are clear of the uncertainty.
  • The widest gap is in agentic & tool use, where GPT-5.2 Codex leads 41.0 to 33.1.
  • The biggest single-benchmark swing is Terminal-Bench: 49.6% for GPT-5 and 66.5% for GPT-5.2 Codex.
  • GPT-5 is cheaper at $1.25 / $10 per million input/output tokens, against $1.75 / $14 for GPT-5.2 Codex.

Side by side

GPT-5 and GPT-5.2 Codex specifications
GPT-5GPT-5.2 Codex
ProviderOpenAIOpenAI
Noometry Index50.942.6
Released2025-08-072025-12-18
WeightsProprietaryProprietary
Context window400K400K
Max output128K128K
Input $ / M tokens$1.25$1.75
Output $ / M tokens$10$14
Results tracked695

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Category by category

Coding GPT-5 leads

GPT-5: 50.3 (#47), GPT-5.2 Codex: 45.5 (#71)

Coding benchmarks
BenchmarkGPT-5GPT-5.2 Codex
SWE-bench Verified (bash only)65%72.8%
LMArena WebDev14181339
ALE-Bench1,1621,300
SWE-bench Verified73.6%—
Aider Polyglot88%—
SWE-bench Multilingual—66.3%
SciCode42.9%—
GSO6.9%—
WeirdML60.7%—
LMArena Coding1436—
AlgoTune1.67—

Agentic & Tool Use GPT-5.2 Codex leads

GPT-5: 33.1 (#56), GPT-5.2 Codex: 41.0 (#22)

Agentic & Tool Use benchmarks
BenchmarkGPT-5GPT-5.2 Codex
Terminal-Bench49.6%66.5%
GDPval34.8%—
Remote Labor Index1.7%—
DeepResearch Bench49.6%—
BALROG32.8%—
LMArena Search1133—
METR Time Horizons69.6%—

Reasoning Not comparable

GPT-5: 38.3 (#64), GPT-5.2 Codex: —

Reasoning benchmarks
BenchmarkGPT-5GPT-5.2 Codex
ARC-AGI-29.9%—
SimpleBench56.7%—
Kagi LLM Benchmark72.7%—
ARC-AGI-165.7%—
CritPt12.6%—
Chess Puzzles37%—
EnigmaEval10.5%—
EBR-Bench12.7%—
LMArena Hard Prompts1416—
Mystery Game Puzzles23%—
DTBench90.7%—
LMCA40%—
Epoch Capabilities Index150—
ForecastBench61.4—

Math Not comparable

GPT-5: 55.0 (#44), GPT-5.2 Codex: —

Math benchmarks
BenchmarkGPT-5GPT-5.2 Codex
FrontierMath (Tiers 1-3)55.4%—
FrontierMath Tier 422%—
OTIS Mock AIME 2024-202591.4%—
ProofBench18%—
Omni-MATH64.7%—
LMArena Math1407—
MATH Level 598.1%—
FrontierMath (Feb 2025 set)32.4%—
FrontierMath Tier 4 (v1)12.5%—

Knowledge Not comparable

GPT-5: 56.6 (#43), GPT-5.2 Codex: —

Knowledge benchmarks
BenchmarkGPT-5GPT-5.2 Codex
GPQA Diamond86.2%—
Humanity's Last Exam25.3%—
SimpleQA Verified50.1%—
MMLU-Pro86.3%—
Confabulations10.3%—
Vectara Hallucination Rate14.7%—
GPQA (HELM)79.2%—
LMArena Expert1419—

Multimodal Not comparable

GPT-5: 46.8 (#13), GPT-5.2 Codex: —

Multimodal benchmarks
BenchmarkGPT-5GPT-5.2 Codex
LMArena Vision1232—
GeoBench81%—
VPCT66%—

Multilingual Not comparable

GPT-5: 51.4 (#110), GPT-5.2 Codex: —

Multilingual benchmarks
BenchmarkGPT-5GPT-5.2 Codex
LMArena Non-English1397—
LMArena Chinese1422—
LMArena French1410—
LMArena German1416—
LMArena Japanese1409—
LMArena Korean1360—
LMArena Russian1406—
LMArena Spanish1399—

Instruction Following Not comparable

GPT-5: 73.8 (#113), GPT-5.2 Codex: —

Instruction Following benchmarks
BenchmarkGPT-5GPT-5.2 Codex
IFEval87.5%—
LMArena Instruction Following1388—

Long Context Not comparable

GPT-5: 69.5 (#2), GPT-5.2 Codex: —

Long Context benchmarks
BenchmarkGPT-5GPT-5.2 Codex
Fiction.LiveBench97.2%—
LMArena Longer Query1399—

Writing & Preference Not comparable

GPT-5: 63.4 (#65), GPT-5.2 Codex: —

Writing & Preference benchmarks
BenchmarkGPT-5GPT-5.2 Codex
LMArena Text1406—
LMArena Creative Writing1365—
Short-Story Creative Writing86%—
EQ-Bench Creative Writing1627—
WildBench85.7%—
LMArena Multi-Turn1426—

Frequently asked questions

Is GPT-5 better than GPT-5.2 Codex?

GPT-5 is the stronger model overall, scoring 50.9 to 42.6 on the Noometry Index.

Which is cheaper, GPT-5 or GPT-5.2 Codex?

GPT-5 is cheaper. It lists at $1.25 per million input tokens and $10 per million output tokens; GPT-5.2 Codex lists at $1.75 and $14.

Is GPT-5 or GPT-5.2 Codex better for coding?

GPT-5 scores higher on coding benchmarks: 50.3 versus 45.5 in the Noometry coding category.

Which has the bigger context window?

Both accept 400K tokens.

How many benchmarks do GPT-5 and GPT-5.2 Codex share?

4 benchmarks have published results for both models. GPT-5 has 69 scored results on Noometry and GPT-5.2 Codex has 5.

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