Model comparison

GPT-5 vs GPT-5.6 Terra

GPT-5.6 Terra is the stronger model overall, scoring 59.2 to 50.9 on the Noometry Index.

Last verified . 40 shared benchmarks.

GPT-5 OpenAI

50.9

Rank #45 Confirmed

GPT-5.6 Terra OpenAI

59.2

Rank #17 Confirmed

Summary

  • They share 40 benchmarks with published results for both. GPT-5 scores higher in 1 category and GPT-5.6 Terra in 9 categories; 9 gaps are clear of the uncertainty.
  • The widest gap is in math, where GPT-5.6 Terra leads 81.6 to 55.0.
  • The biggest single-benchmark swing is ARC-AGI-2: 9.9% for GPT-5 and 83.9% for GPT-5.6 Terra.
  • GPT-5 is cheaper at $1.25 / $10 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 and GPT-5.6 Terra specifications
GPT-5GPT-5.6 Terra
ProviderOpenAIOpenAI
Noometry Index50.959.2
Released2025-08-072026-07-09
WeightsProprietaryProprietary
Context window400K1.05M
Max output128K128K
Input $ / M tokens$1.25$2
Output $ / M tokens$10$12
Results tracked6952

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Category by category

Coding GPT-5.6 Terra leads

GPT-5: 50.3 (#47), GPT-5.6 Terra: 57.7 (#19)

Coding benchmarks
BenchmarkGPT-5GPT-5.6 Terra
LMArena WebDev14181522
SciCode42.9%55%
WeirdML60.7%78.3%
LMArena Coding14361484
ALE-Bench1,1621,951
SWE-bench Verified73.6%—
DeepSWE—69.6%
FrontierCode—41.3%
SWE-bench Verified (bash only)65%—
Aider Polyglot88%—
CursorBench—41.3%
GSO6.9%—
AlgoTune1.67—

Agentic & Tool Use GPT-5.6 Terra leads

GPT-5: 33.1 (#56), GPT-5.6 Terra: 40.1 (#25)

Agentic & Tool Use benchmarks
BenchmarkGPT-5GPT-5.6 Terra
BALROG32.8%53.2%
Terminal-Bench49.6%—
APEX-Agents—58.2%
GDPval34.8%—
Remote Labor Index1.7%—
DeepResearch Bench49.6%—
GDP.pdf—24.7%
LMArena Search1133—
METR Time Horizons69.6%—
Vending-Bench 2—7,343

Reasoning GPT-5.6 Terra leads

GPT-5: 38.3 (#64), GPT-5.6 Terra: 60.7 (#21)

Reasoning benchmarks
BenchmarkGPT-5GPT-5.6 Terra
ARC-AGI-29.9%83.9%
SimpleBench56.7%48.9%
Kagi LLM Benchmark72.7%51.3%
ARC-AGI-165.7%96.5%
CritPt12.6%30%
Chess Puzzles37%54%
LMArena Hard Prompts14161468
Mystery Game Puzzles23%35%
DTBench90.7%93.3%
LMCA40%55%
Epoch Capabilities Index150159.62
NYT Connections (extended)—78.4%
EnigmaEval10.5%—
EBR-Bench12.7%—
Surface Evolver Bench—83.8%
ForecastBench61.4—

Math GPT-5.6 Terra leads

GPT-5: 55.0 (#44), GPT-5.6 Terra: 81.6 (#12)

Math benchmarks
BenchmarkGPT-5GPT-5.6 Terra
FrontierMath (Tiers 1-3)55.4%86%
FrontierMath Tier 422%70.7%
OTIS Mock AIME 2024-202591.4%99.7%
ProofBench18%74%
LMArena Math14071466
Omni-MATH64.7%—
MATH Level 598.1%—
FrontierMath (Feb 2025 set)32.4%—
FrontierMath Tier 4 (v1)12.5%—

Knowledge GPT-5.6 Terra leads

GPT-5: 56.6 (#43), GPT-5.6 Terra: 61.2 (#30)

Knowledge benchmarks
BenchmarkGPT-5GPT-5.6 Terra
GPQA Diamond86.2%93.3%
SimpleQA Verified50.1%43.2%
LMArena Expert14191492
Humanity's Last Exam25.3%—
MMLU-Pro86.3%—
Confabulations10.3%—
Vectara Hallucination Rate14.7%—
GPQA (HELM)79.2%—

Multimodal Too close to call

GPT-5: 46.8 (#13), GPT-5.6 Terra: 47.3 (#11)

Multimodal benchmarks
BenchmarkGPT-5GPT-5.6 Terra
LMArena Vision12321271
GeoBench81%—
VPCT66%—
Blueprint-Bench 2—30.8%
Furniture Assembly—54.2%
LMArena Document—1472

Multilingual GPT-5.6 Terra leads

GPT-5: 51.4 (#110), GPT-5.6 Terra: 54.4 (#44)

Multilingual benchmarks
BenchmarkGPT-5GPT-5.6 Terra
LMArena Non-English13971439
LMArena Chinese14221513
LMArena French14101471
LMArena German14161460
LMArena Japanese14091457
LMArena Korean13601425
LMArena Russian14061450
LMArena Spanish13991448

Instruction Following GPT-5.6 Terra leads

GPT-5: 73.8 (#113), GPT-5.6 Terra: 76.4 (#40)

Instruction Following benchmarks
BenchmarkGPT-5GPT-5.6 Terra
LMArena Instruction Following13881454
IFEval87.5%—

Long Context GPT-5 leads

GPT-5: 69.5 (#2), GPT-5.6 Terra: 44.4 (#68)

Long Context benchmarks
BenchmarkGPT-5GPT-5.6 Terra
LMArena Longer Query13991451
Fiction.LiveBench97.2%—

Writing & Preference GPT-5.6 Terra leads

GPT-5: 63.4 (#65), GPT-5.6 Terra: 70.2 (#23)

Writing & Preference benchmarks
BenchmarkGPT-5GPT-5.6 Terra
LMArena Text14061447
LMArena Creative Writing13651410
EQ-Bench Creative Writing16271855
LMArena Multi-Turn14261449
Short-Story Creative Writing86%—
WildBench85.7%—
EQ-Bench 4—1234

Frequently asked questions

Is GPT-5 better than GPT-5.6 Terra?

GPT-5.6 Terra is the stronger model overall, scoring 59.2 to 50.9 on the Noometry Index.

Which is cheaper, GPT-5 or GPT-5.6 Terra?

GPT-5 is cheaper. It lists at $1.25 per million input tokens and $10 per million output tokens; GPT-5.6 Terra lists at $2 and $12.

Is GPT-5 or GPT-5.6 Terra better for coding?

GPT-5.6 Terra scores higher on coding benchmarks: 57.7 versus 50.3 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 and GPT-5.6 Terra share?

40 benchmarks have published results for both models. GPT-5 has 69 scored results on Noometry and GPT-5.6 Terra has 52.

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