Model comparison

GPT-5.6 Sol vs GPT-5.6 Terra

GPT-5.6 Sol is the stronger model overall, scoring 65.0 to 59.2 on the Noometry Index. GPT-5.6 Terra costs 1.8× less per token, which makes it the better buy when GPT-5.6 Sol's lead doesn't matter for your workload.

Last verified . 52 shared benchmarks.

GPT-5.6 Sol OpenAI

65.0

Rank #7 Confirmed

GPT-5.6 Terra OpenAI

59.2

Rank #17 Confirmed

Summary

  • They share 52 benchmarks with published results for both. GPT-5.6 Sol scores higher in 10 categories and GPT-5.6 Terra in 0 categories; 8 gaps are clear of the uncertainty.
  • The widest gap is in reasoning, where GPT-5.6 Sol leads 74.8 to 60.7.
  • The biggest single-benchmark swing is SimpleQA Verified: 69.7% for GPT-5.6 Sol and 43.2% for GPT-5.6 Terra.
  • GPT-5.6 Terra is cheaper at $2 / $12 per million input/output tokens, against $4 / $20 for GPT-5.6 Sol.

Side by side

GPT-5.6 Sol and GPT-5.6 Terra specifications
GPT-5.6 SolGPT-5.6 Terra
ProviderOpenAIOpenAI
Noometry Index65.059.2
Released2026-07-092026-07-09
WeightsProprietaryProprietary
Context window1.05M1.05M
Max output128K128K
Input $ / M tokens$4$2
Output $ / M tokens$20$12
Results tracked6552

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Category by category

Coding GPT-5.6 Sol leads

GPT-5.6 Sol: 65.1 (#7), GPT-5.6 Terra: 57.7 (#19)

Coding benchmarks
BenchmarkGPT-5.6 SolGPT-5.6 Terra
DeepSWE72.7%69.6%
FrontierCode47.5%41.3%
CursorBench41.7%41.3%
LMArena WebDev16181522
SciCode57.1%55%
WeirdML89.4%78.3%
LMArena Coding14981484
ALE-Bench2,1771,951
FrontierSWE32.2%—
GSO76.5%—
MirrorCode20%—

Agentic & Tool Use GPT-5.6 Sol leads

GPT-5.6 Sol: 50.3 (#7), GPT-5.6 Terra: 40.1 (#25)

Agentic & Tool Use benchmarks
BenchmarkGPT-5.6 SolGPT-5.6 Terra
APEX-Agents51.4%58.2%
BALROG60%53.2%
GDP.pdf30.7%24.7%
Vending-Bench 29,6197,343
OSWorld 2.027.3%—
τ²-bench Banking46.9%—
PostTrainBench36.2%—
GBAEval52.6%—
LMArena Search1257—

Reasoning GPT-5.6 Sol leads

GPT-5.6 Sol: 74.8 (#8), GPT-5.6 Terra: 60.7 (#21)

Reasoning benchmarks
BenchmarkGPT-5.6 SolGPT-5.6 Terra
ARC-AGI-292.5%83.9%
SimpleBench71.7%48.9%
Kagi LLM Benchmark67%51.3%
NYT Connections (extended)93.8%78.4%
ARC-AGI-197.5%96.5%
CritPt32.3%30%
Chess Puzzles64%54%
LMArena Hard Prompts14841468
Mystery Game Puzzles58%35%
DTBench96%93.3%
LMCA59.2%55%
Surface Evolver Bench93.1%83.8%
Epoch Capabilities Index161.66159.62
EnigmaEval37.1%—
EBR-Bench44.8%—
Bench to the Future 30.14—

Math GPT-5.6 Sol leads

GPT-5.6 Sol: 85.6 (#9), GPT-5.6 Terra: 81.6 (#12)

Math benchmarks
BenchmarkGPT-5.6 SolGPT-5.6 Terra
FrontierMath (Tiers 1-3)89.1%86%
FrontierMath Tier 482.9%70.7%
OTIS Mock AIME 2024-2025100%99.7%
ProofBench83%74%
LMArena Math14741466
FrontierMath Erdős0%—

Knowledge GPT-5.6 Sol leads

GPT-5.6 Sol: 64.3 (#18), GPT-5.6 Terra: 61.2 (#30)

Knowledge benchmarks
BenchmarkGPT-5.6 SolGPT-5.6 Terra
GPQA Diamond93.5%93.3%
SimpleQA Verified69.7%43.2%
LMArena Expert15161492
Vectara Hallucination Rate12.4%—

Multimodal GPT-5.6 Sol leads

GPT-5.6 Sol: 48.6 (#9), GPT-5.6 Terra: 47.3 (#11)

Multimodal benchmarks
BenchmarkGPT-5.6 SolGPT-5.6 Terra
LMArena Vision12811271
Blueprint-Bench 233.6%30.8%
Furniture Assembly56.7%54.2%
LMArena Document14831472

Multilingual Too close to call

GPT-5.6 Sol: 55.3 (#32), GPT-5.6 Terra: 54.4 (#44)

Multilingual benchmarks
BenchmarkGPT-5.6 SolGPT-5.6 Terra
LMArena Non-English14521439
LMArena Chinese15271513
LMArena French14771471
LMArena German14761460
LMArena Japanese14711457
LMArena Korean14421425
LMArena Russian14681450
LMArena Spanish14411448

Instruction Following GPT-5.6 Sol leads

GPT-5.6 Sol: 77.7 (#16), GPT-5.6 Terra: 76.4 (#40)

Instruction Following benchmarks
BenchmarkGPT-5.6 SolGPT-5.6 Terra
LMArena Instruction Following14821454

Long Context Too close to call

GPT-5.6 Sol: 45.4 (#42), GPT-5.6 Terra: 44.4 (#68)

Long Context benchmarks
BenchmarkGPT-5.6 SolGPT-5.6 Terra
LMArena Longer Query14801451

Writing & Preference GPT-5.6 Sol leads

GPT-5.6 Sol: 73.3 (#12), GPT-5.6 Terra: 70.2 (#23)

Writing & Preference benchmarks
BenchmarkGPT-5.6 SolGPT-5.6 Terra
LMArena Text14571447
LMArena Creative Writing14481410
EQ-Bench Creative Writing19721855
EQ-Bench 412501234
LMArena Multi-Turn14601449

Frequently asked questions

Is GPT-5.6 Sol better than GPT-5.6 Terra?

GPT-5.6 Sol is the stronger model overall, scoring 65.0 to 59.2 on the Noometry Index. GPT-5.6 Terra costs 1.8× less per token, which makes it the better buy when GPT-5.6 Sol's lead doesn't matter for your workload.

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

GPT-5.6 Terra is cheaper. It lists at $2 per million input tokens and $12 per million output tokens; GPT-5.6 Sol lists at $4 and $20.

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

GPT-5.6 Sol scores higher on coding benchmarks: 65.1 versus 57.7 in the Noometry coding category.

Which has the bigger context window?

Both accept 1.05M tokens.

How many benchmarks do GPT-5.6 Sol and GPT-5.6 Terra share?

52 benchmarks have published results for both models. GPT-5.6 Sol has 65 scored results on Noometry and GPT-5.6 Terra has 52.

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