Model comparison

GPT-5.1 vs GPT-6.1 Sol

GPT-6.1 Sol is the stronger model overall, scoring 65.6 to 49.0 on the Noometry Index.

Last verified . 24 shared benchmarks.

GPT-5.1 OpenAI

49.0

Rank #53 Confirmed

GPT-6.1 Sol OpenAI

65.6

Rank #6 Confirmed

Summary

  • They share 24 benchmarks with published results for both. GPT-5.1 scores higher in 3 categories and GPT-6.1 Sol in 7 categories; 8 gaps are clear of the uncertainty.
  • The widest gap is in reasoning, where GPT-6.1 Sol leads 81.9 to 39.8.
  • The biggest single-benchmark swing is ARC-AGI-2: 17.6% for GPT-5.1 and 94.2% for GPT-6.1 Sol.
  • GPT-5.1 is cheaper at $1.25 / $10 per million input/output tokens, against $2 / $10 for GPT-6.1 Sol.
  • GPT-6.1 Sol accepts more context: 1.05M tokens versus 400K.

Side by side

GPT-5.1 and GPT-6.1 Sol specifications
GPT-5.1GPT-6.1 Sol
ProviderOpenAIOpenAI
Noometry Index49.065.6
Released2025-11-132026-09-29
WeightsProprietaryProprietary
Context window400K1.05M
Max output128K128K
Input $ / M tokens$1.25$2
Output $ / M tokens$10$10
Results tracked6334

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Category by category

Coding GPT-6.1 Sol leads

GPT-5.1: 46.4 (#66), GPT-6.1 Sol: 63.2 (#8)

Coding benchmarks
BenchmarkGPT-5.1GPT-6.1 Sol
LMArena WebDev13951755
SciCode43.3%55.8%
LMArena Coding14541487
SWE-bench Verified68%—
DeepSWE—75.2%
FrontierCode—50.2%
SWE-bench Verified (bash only)66%—
GSO13.7%—
WeirdML60.8%—
LiveBench Coding72.5%—
ALE-Bench1,192—

Agentic & Tool Use GPT-6.1 Sol leads

GPT-5.1: 32.7 (#60), GPT-6.1 Sol: 39.6 (#26)

Agentic & Tool Use benchmarks
BenchmarkGPT-5.1GPT-6.1 Sol
Terminal-Bench47.6%—
APEX-Agents—60%
DeepResearch Bench42.8%—
GDP.pdf—32%
LMArena Search1199—
Vending-Bench 21,473—

Reasoning GPT-6.1 Sol leads

GPT-5.1: 39.8 (#58), GPT-6.1 Sol: 81.9 (#2)

Reasoning benchmarks
BenchmarkGPT-5.1GPT-6.1 Sol
ARC-AGI-217.6%94.2%
ARC-AGI-172.8%98.5%
CritPt4.9%31.7%
Chess Puzzles32%61%
LMArena Hard Prompts14571466
Mystery Game Puzzles19%80%
Epoch Capabilities Index149.64166.09
SimpleBench53.2%—
NYT Connections (extended)—95.5%
EnigmaEval11.2%—
EBR-Bench—54.3%
LiveBench Reasoning95.8%—
DTBench90.1%—
LiveBench Data Analysis72.1%—
LMCA43.9%—
ForecastBench58.1—
LiveBench78.8%—

Math GPT-6.1 Sol leads

GPT-5.1: 52.2 (#51), GPT-6.1 Sol: 93.7 (#1)

Math benchmarks
BenchmarkGPT-5.1GPT-6.1 Sol
OTIS Mock AIME 2024-202588.6%100%
LMArena Math14471464
FrontierMath (Tiers 1-3)—93.7%
FrontierMath Tier 4—100%
ProofBench—99%
Omni-MATH46.4%—
LiveBench Math94.5%—
FrontierMath (Feb 2025 set)31%—
FrontierMath Tier 4 (v1)12.5%—

Knowledge GPT-6.1 Sol leads

GPT-5.1: 50.6 (#71), GPT-6.1 Sol: 71.8 (#4)

Knowledge benchmarks
BenchmarkGPT-5.1GPT-6.1 Sol
GPQA Diamond87.6%95.4%
SimpleQA Verified48%73.9%
LMArena Expert14701502
Humanity's Last Exam23.7%—
MMLU-Pro57.9%—
Vectara Hallucination Rate10.9%—
GPQA (HELM)44.2%—

Multimodal GPT-6.1 Sol leads

GPT-5.1: 44.8 (#19), GPT-6.1 Sol: 52.7 (#5)

Multimodal benchmarks
BenchmarkGPT-5.1GPT-6.1 Sol
LMArena Vision12501288
VPCT58.7%—
Furniture Assembly—80%
LMArena Document1403—

Multilingual Too close to call

GPT-5.1: 53.8 (#56), GPT-6.1 Sol: 54.3 (#46)

Multilingual benchmarks
BenchmarkGPT-5.1GPT-6.1 Sol
LMArena Non-English14311438
LMArena Chinese14951477
LMArena Russian14351455
LMArena French1450—
LMArena German1438—
LMArena Japanese1453—
LMArena Korean1401—
LMArena Spanish1433—

Instruction Following GPT-5.1 leads

GPT-5.1: 83.9 (#1), GPT-6.1 Sol: 77.0 (#29)

Instruction Following benchmarks
BenchmarkGPT-5.1GPT-6.1 Sol
LMArena Instruction Following14431468
LiveBench Instruction Following93.3%—
IFEval93.5%—

Long Context GPT-5.1 leads

GPT-5.1: 47.6 (#14), GPT-6.1 Sol: 44.9 (#54)

Long Context benchmarks
BenchmarkGPT-5.1GPT-6.1 Sol
LMArena Longer Query14471465
CL-bench23.7%—
CL-bench Life17.3%—

Writing & Preference Too close to call

GPT-5.1: 64.5 (#55), GPT-6.1 Sol: 63.6 (#63)

Writing & Preference benchmarks
BenchmarkGPT-5.1GPT-6.1 Sol
LMArena Text14431447
LMArena Creative Writing14271432
LMArena Multi-Turn14501449
WildBench86.3%—
LiveBench Language80.2%—

Frequently asked questions

Is GPT-5.1 better than GPT-6.1 Sol?

GPT-6.1 Sol is the stronger model overall, scoring 65.6 to 49.0 on the Noometry Index.

Which is cheaper, GPT-5.1 or GPT-6.1 Sol?

GPT-5.1 is cheaper. It lists at $1.25 per million input tokens and $10 per million output tokens; GPT-6.1 Sol lists at $2 and $10.

Is GPT-5.1 or GPT-6.1 Sol better for coding?

GPT-6.1 Sol scores higher on coding benchmarks: 63.2 versus 46.4 in the Noometry coding category.

Which has the bigger context window?

GPT-6.1 Sol does, with 1.05M tokens against 400K.

How many benchmarks do GPT-5.1 and GPT-6.1 Sol share?

24 benchmarks have published results for both models. GPT-5.1 has 63 scored results on Noometry and GPT-6.1 Sol has 34.

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