Noometry

Model comparison

GPT-4.1 nano vs GPT-5.1-Codex

GPT-5.1-Codex is the stronger model overall, scoring 38.6 to 27.9 on the Noometry Index. GPT-4.1 nano costs 20× less per token, which makes it the better buy when GPT-5.1-Codex's lead doesn't matter for your workload.

Last verified . 0 shared benchmarks.

GPT-4.1 nano OpenAI

27.9

Rank #327 Confirmed

GPT-5.1-Codex OpenAI

38.6

Rank #186 Reported

Summary

  • The widest gap is in coding, where GPT-5.1-Codex leads 41.9 to 24.1.
  • GPT-4.1 nano is cheaper at $0.10 / $0.40 per million input/output tokens, against $1.25 / $10 for GPT-5.1-Codex.
  • GPT-4.1 nano accepts more context: 1.05M tokens versus 400K.

Side by side

GPT-4.1 nanoGPT-5.1-Codex
ProviderOpenAIOpenAI
Noometry Index27.938.6
Released2025-04-142025-11-12
WeightsProprietaryProprietary
Context window1.05M400K
Max output33K128K
Input $ / M tokens$0.10$1.25
Output $ / M tokens$0.40$10
Results tracked386

Sponsored placements are available on pages like this one. Advertise on Noometry

Category by category

Coding GPT-5.1-Codex leads

GPT-4.1 nano: 24.1 (#330), GPT-5.1-Codex: 41.9 (#116)

BenchmarkGPT-4.1 nanoGPT-5.1-Codex
SWE-bench Verified (bash only)—66%
Aider Polyglot8.9%—
LMArena WebDev—1337
SciCode25.9%—
WeirdML19%—
LMArena Coding1306—
ALE-Bench—1,245

Agentic & Tool Use GPT-5.1-Codex leads

GPT-4.1 nano: 26.5 (#104), GPT-5.1-Codex: 38.0 (#33)

BenchmarkGPT-4.1 nanoGPT-5.1-Codex
Terminal-Bench—60.4%
Berkeley Function Calling Leaderboard33%—
METR Time Horizons—70.8%

Reasoning Not comparable

GPT-4.1 nano: 8.5 (#349), GPT-5.1-Codex: —

BenchmarkGPT-4.1 nanoGPT-5.1-Codex
ARC-AGI-20%—
Kagi LLM Benchmark33.3%—
ARC-AGI-10%—
CritPt0%—
LMArena Hard Prompts1286—
DTBench52.5%—
LMCA5.5%—
Epoch Capabilities Index129.62—

Math GPT-5.1-Codex leads

GPT-4.1 nano: 26.9 (#252), GPT-5.1-Codex: 30.3 (#235)

BenchmarkGPT-4.1 nanoGPT-5.1-Codex
OTIS Mock AIME 2024-202528.9%—
ProofBench—9%
Omni-MATH36.7%—
LMArena Math1274—
MATH Level 570%—
FrontierMath (Feb 2025 set)1%—

Knowledge Not comparable

GPT-4.1 nano: 21.8 (#273), GPT-5.1-Codex: —

BenchmarkGPT-4.1 nanoGPT-5.1-Codex
GPQA Diamond48.9%—
SimpleQA Verified6%—
MMLU-Pro55%—
GPQA (HELM)50.7%—
LMArena Expert1272—

Multimodal Not comparable

GPT-4.1 nano: 29.2 (#113), GPT-5.1-Codex: —

BenchmarkGPT-4.1 nanoGPT-5.1-Codex
LMArena Vision1063—

Multilingual Not comparable

GPT-4.1 nano: 41.6 (#205), GPT-5.1-Codex: —

BenchmarkGPT-4.1 nanoGPT-5.1-Codex
LMArena Non-English1260—
LMArena Chinese1270—
LMArena German1288—
LMArena Japanese1198—
LMArena Russian1261—

Instruction Following Not comparable

GPT-4.1 nano: 67.8 (#193), GPT-5.1-Codex: —

BenchmarkGPT-4.1 nanoGPT-5.1-Codex
IFEval84.3%—
LMArena Instruction Following1267—

Long Context Not comparable

GPT-4.1 nano: 23.7 (#296), GPT-5.1-Codex: —

BenchmarkGPT-4.1 nanoGPT-5.1-Codex
Fiction.LiveBench25%—
LMArena Longer Query1283—

Writing & Preference Not comparable

GPT-4.1 nano: 40.5 (#243), GPT-5.1-Codex: —

BenchmarkGPT-4.1 nanoGPT-5.1-Codex
LMArena Text1285—
LMArena Creative Writing1260—
EQ-Bench Creative Writing946—
WildBench81.2%—
LMArena Multi-Turn1277—

Frequently asked questions

Is GPT-4.1 nano better than GPT-5.1-Codex?

GPT-5.1-Codex is the stronger model overall, scoring 38.6 to 27.9 on the Noometry Index. GPT-4.1 nano costs 20× less per token, which makes it the better buy when GPT-5.1-Codex's lead doesn't matter for your workload.

Which is cheaper, GPT-4.1 nano or GPT-5.1-Codex?

GPT-4.1 nano is cheaper. It lists at $0.10 per million input tokens and $0.40 per million output tokens; GPT-5.1-Codex lists at $1.25 and $10.

Is GPT-4.1 nano or GPT-5.1-Codex better for coding?

GPT-5.1-Codex scores higher on coding benchmarks: 41.9 versus 24.1 in the Noometry coding category.

Which has the bigger context window?

GPT-4.1 nano does, with 1.05M tokens against 400K.

How many benchmarks do GPT-4.1 nano and GPT-5.1-Codex share?

0 benchmarks have published results for both models. GPT-4.1 nano has 38 scored results on Noometry and GPT-5.1-Codex has 6.

Related comparisons

Go deeper