Model comparison

GPT-5.6 Terra vs o3-pro

GPT-5.6 Terra is the stronger model overall, scoring 59.2 to 42.9 on the Noometry Index.

Last verified . 7 shared benchmarks.

GPT-5.6 Terra OpenAI

59.2

Rank #17 Confirmed

o3-pro OpenAI

42.9

Rank #105 Confirmed

Summary

  • They share 7 benchmarks with published results for both. GPT-5.6 Terra scores higher in 4 categories and o3-pro in 1 category; 5 gaps are clear of the uncertainty.
  • The widest gap is in reasoning, where GPT-5.6 Terra leads 60.7 to 23.8.
  • The biggest single-benchmark swing is ARC-AGI-2: 83.9% for GPT-5.6 Terra and 4.9% for o3-pro.
  • GPT-5.6 Terra is cheaper at $2 / $12 per million input/output tokens, against $20 / $80 for o3-pro.
  • GPT-5.6 Terra accepts more context: 1.05M tokens versus 200K.

Side by side

GPT-5.6 Terra and o3-pro specifications
GPT-5.6 Terrao3-pro
ProviderOpenAIOpenAI
Noometry Index59.242.9
Released2026-07-092025-06-10
WeightsProprietaryProprietary
Context window1.05M200K
Max output128K100K
Input $ / M tokens$2$20
Output $ / M tokens$12$80
Results tracked5212

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Category by category

Coding GPT-5.6 Terra leads

GPT-5.6 Terra: 57.7 (#19), o3-pro: 55.5 (#24)

Coding benchmarks
BenchmarkGPT-5.6 Terrao3-pro
WeirdML78.3%58.2%
DeepSWE69.6%—
FrontierCode41.3%—
Aider Polyglot—84.9%
CursorBench41.3%—
LMArena WebDev1522—
SciCode55%—
LMArena Coding1484—
ALE-Bench1,951—

Agentic & Tool Use Not comparable

GPT-5.6 Terra: 40.1 (#25), o3-pro: —

Agentic & Tool Use benchmarks
BenchmarkGPT-5.6 Terrao3-pro
APEX-Agents58.2%—
BALROG53.2%—
GDP.pdf24.7%—
Vending-Bench 27,343—

Reasoning GPT-5.6 Terra leads

GPT-5.6 Terra: 60.7 (#21), o3-pro: 23.8 (#171)

Reasoning benchmarks
BenchmarkGPT-5.6 Terrao3-pro
ARC-AGI-283.9%4.9%
Kagi LLM Benchmark51.3%72.1%
ARC-AGI-196.5%59.3%
DTBench93.3%86.9%
LMCA55%38.5%
Epoch Capabilities Index159.62147.42
SimpleBench48.9%—
NYT Connections (extended)78.4%—
CritPt30%—
Chess Puzzles54%—
LMArena Hard Prompts1468—
Mystery Game Puzzles35%—
Surface Evolver Bench83.8%—

Math Not comparable

GPT-5.6 Terra: 81.6 (#12), o3-pro: —

Math benchmarks
BenchmarkGPT-5.6 Terrao3-pro
FrontierMath (Tiers 1-3)86%—
FrontierMath Tier 470.7%—
OTIS Mock AIME 2024-202599.7%—
ProofBench74%—
LMArena Math1466—

Knowledge GPT-5.6 Terra leads

GPT-5.6 Terra: 61.2 (#30), o3-pro: 29.5 (#238)

Knowledge benchmarks
BenchmarkGPT-5.6 Terrao3-pro
GPQA Diamond93.3%—
SimpleQA Verified43.2%—
Confabulations—14.2%
Vectara Hallucination Rate—23.3%
LMArena Expert1492—

Multimodal Not comparable

GPT-5.6 Terra: 47.3 (#11), o3-pro: —

Multimodal benchmarks
BenchmarkGPT-5.6 Terrao3-pro
LMArena Vision1271—
Blueprint-Bench 230.8%—
Furniture Assembly54.2%—
LMArena Document1472—

Multilingual Not comparable

GPT-5.6 Terra: 54.4 (#44), o3-pro: —

Multilingual benchmarks
BenchmarkGPT-5.6 Terrao3-pro
LMArena Non-English1439—
LMArena Chinese1513—
LMArena French1471—
LMArena German1460—
LMArena Japanese1457—
LMArena Korean1425—
LMArena Russian1450—
LMArena Spanish1448—

Instruction Following Not comparable

GPT-5.6 Terra: 76.4 (#40), o3-pro: —

Instruction Following benchmarks
BenchmarkGPT-5.6 Terrao3-pro
LMArena Instruction Following1454—

Long Context o3-pro leads

GPT-5.6 Terra: 44.4 (#68), o3-pro: 72.2 (#1)

Long Context benchmarks
BenchmarkGPT-5.6 Terrao3-pro
Fiction.LiveBench—97.2%
LMArena Longer Query1451—

Writing & Preference GPT-5.6 Terra leads

GPT-5.6 Terra: 70.2 (#23), o3-pro: 57.1 (#133)

Writing & Preference benchmarks
BenchmarkGPT-5.6 Terrao3-pro
LMArena Text1447—
LMArena Creative Writing1410—
Short-Story Creative Writing—84.4%
EQ-Bench Creative Writing1855—
EQ-Bench 41234—
LMArena Multi-Turn1449—

Frequently asked questions

Is GPT-5.6 Terra better than o3-pro?

GPT-5.6 Terra is the stronger model overall, scoring 59.2 to 42.9 on the Noometry Index.

Which is cheaper, GPT-5.6 Terra or o3-pro?

GPT-5.6 Terra is cheaper. It lists at $2 per million input tokens and $12 per million output tokens; o3-pro lists at $20 and $80.

Is GPT-5.6 Terra or o3-pro better for coding?

GPT-5.6 Terra scores higher on coding benchmarks: 57.7 versus 55.5 in the Noometry coding category.

Which has the bigger context window?

GPT-5.6 Terra does, with 1.05M tokens against 200K.

How many benchmarks do GPT-5.6 Terra and o3-pro share?

7 benchmarks have published results for both models. GPT-5.6 Terra has 52 scored results on Noometry and o3-pro has 12.

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