Model comparison

GPT-5.1-Codex-mini vs GPT-5.6 Terra

GPT-5.6 Terra has enough public results to be ranked (#15); GPT-5.1-Codex-mini does not yet, so treat this comparison as directional.

Last verified . 1 shared benchmarks.

GPT-5.1-Codex-mini OpenAI

36.9

Unranked Sparse

GPT-5.6 Terra OpenAI

59.1

Rank #15 Confirmed

Summary

  • They share 1 benchmark with published results for both. GPT-5.1-Codex-mini scores higher in 0 categories and GPT-5.6 Terra in 2 categories; 2 gaps are clear of the uncertainty.
  • The widest gap is in coding, where GPT-5.6 Terra leads 57.1 to 31.4.
  • GPT-5.1-Codex-mini is cheaper at $0.25 / $2 per million input/output tokens, against $2 / $12 for GPT-5.6 Terra.
  • GPT-5.6 Terra accepts more context: 1.05M tokens versus 400K.

Side by side

GPT-5.1-Codex-mini and GPT-5.6 Terra specifications
GPT-5.1-Codex-miniGPT-5.6 Terra
ProviderOpenAIOpenAI
Noometry Index36.959.1
Released2025-11-122026-07-09
WeightsProprietaryProprietary
Context window400K1.05M
Max output128K128K
Input $ / M tokens$0.25$2
Output $ / M tokens$2$12
Results tracked252

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Category by category

Coding GPT-5.6 Terra leads

GPT-5.1-Codex-mini: 31.4, GPT-5.6 Terra: 57.1 (#16)

Coding benchmarks
BenchmarkGPT-5.1-Codex-miniGPT-5.6 Terra
LMArena WebDev12441520
DeepSWE—69.6%
FrontierCode—41.3%
CursorBench—41.3%
SciCode—55%
WeirdML—78.3%
LMArena Coding—1484
ALE-Bench—1,951

Agentic & Tool Use GPT-5.6 Terra leads

GPT-5.1-Codex-mini: 38.3, GPT-5.6 Terra: 40.2 (#23)

Agentic & Tool Use benchmarks
BenchmarkGPT-5.1-Codex-miniGPT-5.6 Terra
Terminal-Bench61.6%—
APEX-Agents—58.2%
BALROG—53.2%
GDP.pdf—24.7%
Vending-Bench 2—7,343

Reasoning Not comparable

GPT-5.1-Codex-mini: —, GPT-5.6 Terra: 60.6 (#19)

Reasoning benchmarks
BenchmarkGPT-5.1-Codex-miniGPT-5.6 Terra
ARC-AGI-2—83.9%
SimpleBench—48.9%
Kagi LLM Benchmark—51.3%
NYT Connections (extended)—78.4%
ARC-AGI-1—96.5%
CritPt—30%
Chess Puzzles—54%
LMArena Hard Prompts—1467
Mystery Game Puzzles—35%
DTBench—93.3%
LMCA—55%
Surface Evolver Bench—83.8%
Epoch Capabilities Index—159.31

Math Not comparable

GPT-5.1-Codex-mini: —, GPT-5.6 Terra: 81.5 (#10)

Math benchmarks
BenchmarkGPT-5.1-Codex-miniGPT-5.6 Terra
FrontierMath (Tiers 1-3)—86%
FrontierMath Tier 4—70.7%
OTIS Mock AIME 2024-2025—99.7%
ProofBench—74%
LMArena Math—1463

Knowledge Not comparable

GPT-5.1-Codex-mini: —, GPT-5.6 Terra: 61.3 (#27)

Knowledge benchmarks
BenchmarkGPT-5.1-Codex-miniGPT-5.6 Terra
GPQA Diamond—93.3%
SimpleQA Verified—43.2%
LMArena Expert—1492

Multimodal Not comparable

GPT-5.1-Codex-mini: —, GPT-5.6 Terra: 47.5 (#10)

Multimodal benchmarks
BenchmarkGPT-5.1-Codex-miniGPT-5.6 Terra
LMArena Vision—1271
Blueprint-Bench 2—30.8%
Furniture Assembly—54.2%
LMArena Document—1472

Multilingual Not comparable

GPT-5.1-Codex-mini: —, GPT-5.6 Terra: 54.5 (#42)

Multilingual benchmarks
BenchmarkGPT-5.1-Codex-miniGPT-5.6 Terra
LMArena Non-English—1439
LMArena Chinese—1514
LMArena French—1476
LMArena German—1462
LMArena Japanese—1446
LMArena Korean—1420
LMArena Russian—1450
LMArena Spanish—1455

Instruction Following Not comparable

GPT-5.1-Codex-mini: —, GPT-5.6 Terra: 76.6 (#38)

Instruction Following benchmarks
BenchmarkGPT-5.1-Codex-miniGPT-5.6 Terra
LMArena Instruction Following—1453

Long Context Not comparable

GPT-5.1-Codex-mini: —, GPT-5.6 Terra: 44.4 (#64)

Long Context benchmarks
BenchmarkGPT-5.1-Codex-miniGPT-5.6 Terra
LMArena Longer Query—1452

Writing & Preference Not comparable

GPT-5.1-Codex-mini: —, GPT-5.6 Terra: 70.4 (#21)

Writing & Preference benchmarks
BenchmarkGPT-5.1-Codex-miniGPT-5.6 Terra
LMArena Text—1446
LMArena Creative Writing—1411
EQ-Bench Creative Writing—1855
EQ-Bench 4—1234
LMArena Multi-Turn—1451

Frequently asked questions

Is GPT-5.1-Codex-mini better than GPT-5.6 Terra?

GPT-5.6 Terra has enough public results to be ranked (#15); GPT-5.1-Codex-mini does not yet, so treat this comparison as directional.

Which is cheaper, GPT-5.1-Codex-mini or GPT-5.6 Terra?

GPT-5.1-Codex-mini is cheaper. It lists at $0.25 per million input tokens and $2 per million output tokens; GPT-5.6 Terra lists at $2 and $12.

Is GPT-5.1-Codex-mini or GPT-5.6 Terra better for coding?

GPT-5.6 Terra scores higher on coding benchmarks: 57.1 versus 31.4 in the Noometry coding category.

Which has the bigger context window?

GPT-5.6 Terra does, with 1.05M tokens against 400K.

How many benchmarks do GPT-5.1-Codex-mini and GPT-5.6 Terra share?

1 benchmark has published results for both models. GPT-5.1-Codex-mini has 2 scored results on Noometry and GPT-5.6 Terra has 52.

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