Model comparison

GPT-5 Nano vs Solar Pro4

Solar Pro4 is the stronger model overall, scoring 42.1 to 33.5 on the Noometry Index. GPT-5 Nano costs 3.8× less per token, which makes it the better buy when Solar Pro4's lead doesn't matter for your workload.

Last verified . 16 shared benchmarks.

GPT-5 Nano OpenAI

33.5

Rank #241 Confirmed

Solar Pro4 Upstage

42.1

Rank #121 Confirmed

Summary

  • They share 16 benchmarks with published results for both. GPT-5 Nano scores higher in 1 category and Solar Pro4 in 7 categories; 8 gaps are clear of the uncertainty.
  • The widest gap is in writing & preference, where Solar Pro4 leads 56.5 to 39.1.
  • GPT-5 Nano is cheaper at $0.05 / $0.40 per million input/output tokens, against $0.30 / $1.20 for Solar Pro4.
  • Solar Pro4 accepts more context: 524K tokens versus 400K.

Side by side

GPT-5 Nano and Solar Pro4 specifications
GPT-5 NanoSolar Pro4
ProviderOpenAIUpstage
Noometry Index33.542.1
Released2025-08-072026-08-06
WeightsProprietaryProprietary
Context window400K524K
Max output128K131K
Input $ / M tokens$0.05$0.30
Output $ / M tokens$0.40$1.20
Results tracked4918

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Category by category

Coding Solar Pro4 leads

GPT-5 Nano: 33.6 (#254), Solar Pro4: 40.1 (#149)

Coding benchmarks
BenchmarkGPT-5 NanoSolar Pro4
LMArena Coding13511437
SWE-bench Verified (bash only)34.8%—
LMArena WebDev—1371
WeirdML38.1%—
ALE-Bench718.67—

Agentic & Tool Use Not comparable

GPT-5 Nano: 25.8 (#106), Solar Pro4: —

Agentic & Tool Use benchmarks
BenchmarkGPT-5 NanoSolar Pro4
Terminal-Bench21.8%—
Berkeley Function Calling Leaderboard51.5%—

Reasoning Solar Pro4 leads

GPT-5 Nano: 16.3 (#306), Solar Pro4: 28.5 (#104)

Reasoning benchmarks
BenchmarkGPT-5 NanoSolar Pro4
LMArena Hard Prompts13281399
ARC-AGI-22.6%—
Kagi LLM Benchmark62.2%—
ARC-AGI-120.7%—
Chess Puzzles27%—
Mystery Game Puzzles9%—
DTBench62.7%—
LMCA7.9%—
Epoch Capabilities Index139.38—
ForecastBench59.1—

Math Solar Pro4 leads

GPT-5 Nano: 29.4 (#241), Solar Pro4: 38.8 (#128)

Math benchmarks
BenchmarkGPT-5 NanoSolar Pro4
LMArena Math13171416
FrontierMath (Tiers 1-3)20%—
FrontierMath Tier 42.4%—
OTIS Mock AIME 2024-202581.1%—
ProofBench12%—
Omni-MATH54.6%—
MATH Level 595.2%—
FrontierMath (Feb 2025 set)8.3%—
FrontierMath Tier 4 (v1)2.1%—

Knowledge Solar Pro4 leads

GPT-5 Nano: 35.9 (#178), Solar Pro4: 39.8 (#129)

Knowledge benchmarks
BenchmarkGPT-5 NanoSolar Pro4
LMArena Expert13211427
GPQA Diamond69.4%—
SimpleQA Verified11.7%—
MMLU-Pro77.8%—
Vectara Hallucination Rate10.5%—
GPQA (HELM)67.9%—

Multimodal Not comparable

GPT-5 Nano: 31.3 (#108), Solar Pro4: —

Multimodal benchmarks
BenchmarkGPT-5 NanoSolar Pro4
LMArena Vision1159—
VPCT37.2%—

Multilingual Solar Pro4 leads

GPT-5 Nano: 45.3 (#172), Solar Pro4: 48.7 (#139)

Multilingual benchmarks
BenchmarkGPT-5 NanoSolar Pro4
LMArena Non-English13131361
LMArena Chinese13561415
LMArena German13271364
LMArena Japanese12261309
LMArena Korean12691382
LMArena Russian12961360
LMArena Spanish13601401
LMArena French—1397

Instruction Following GPT-5 Nano leads

GPT-5 Nano: 75.0 (#79), Solar Pro4: 72.7 (#132)

Instruction Following benchmarks
BenchmarkGPT-5 NanoSolar Pro4
LMArena Instruction Following13061377
IFEval93.2%—

Long Context Solar Pro4 leads

GPT-5 Nano: 31.3 (#281), Solar Pro4: 42.1 (#130)

Long Context benchmarks
BenchmarkGPT-5 NanoSolar Pro4
LMArena Longer Query13121381
Fiction.LiveBench44.4%—

Writing & Preference Solar Pro4 leads

GPT-5 Nano: 39.1 (#249), Solar Pro4: 56.5 (#138)

Writing & Preference benchmarks
BenchmarkGPT-5 NanoSolar Pro4
LMArena Text13201386
LMArena Creative Writing12491316
LMArena Multi-Turn13111385
EQ-Bench Creative Writing705—
WildBench80.6%—

Frequently asked questions

Is GPT-5 Nano better than Solar Pro4?

Solar Pro4 is the stronger model overall, scoring 42.1 to 33.5 on the Noometry Index. GPT-5 Nano costs 3.8× less per token, which makes it the better buy when Solar Pro4's lead doesn't matter for your workload.

Which is cheaper, GPT-5 Nano or Solar Pro4?

GPT-5 Nano is cheaper. It lists at $0.05 per million input tokens and $0.40 per million output tokens; Solar Pro4 lists at $0.30 and $1.20.

Is GPT-5 Nano or Solar Pro4 better for coding?

Solar Pro4 scores higher on coding benchmarks: 40.1 versus 33.6 in the Noometry coding category.

Which has the bigger context window?

Solar Pro4 does, with 524K tokens against 400K.

How many benchmarks do GPT-5 Nano and Solar Pro4 share?

16 benchmarks have published results for both models. GPT-5 Nano has 49 scored results on Noometry and Solar Pro4 has 18.

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