Model comparison

GPT-5 Nano vs Mistral Small 3

GPT-5 Nano is the stronger model overall, scoring 33.5 to 31.2 on the Noometry Index. Mistral Small 3 costs 2.4× less per token, which makes it the better buy when GPT-5 Nano's lead doesn't matter for your workload.

Last verified . 20 shared benchmarks.

GPT-5 Nano OpenAI

33.5

Rank #241 Confirmed

Mistral Small 3 Mistral AI

31.2

Rank #278 Confirmed

Summary

  • They share 20 benchmarks with published results for both. GPT-5 Nano scores higher in 5 categories and Mistral Small 3 in 3 categories; 8 gaps are clear of the uncertainty.
  • The widest gap is in math, where GPT-5 Nano leads 29.4 to 16.3.
  • The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 81.1% for GPT-5 Nano and 6.7% for Mistral Small 3.
  • Mistral Small 3 is cheaper at $0.05 / $0.08 per million input/output tokens, against $0.05 / $0.40 for GPT-5 Nano.
  • GPT-5 Nano accepts more context: 400K tokens versus 33K.
  • Mistral Small 3 has downloadable open weights; the other is API-only.

Side by side

GPT-5 Nano and Mistral Small 3 specifications
GPT-5 NanoMistral Small 3
ProviderOpenAIMistral AI
Noometry Index33.531.2
Released2025-08-072025-01-30
WeightsProprietaryOpen
Context window400K33K
Max output128K16K
Input $ / M tokens$0.05$0.05
Output $ / M tokens$0.40$0.08
Results tracked4924

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Category by category

Coding Mistral Small 3 leads

GPT-5 Nano: 33.6 (#254), Mistral Small 3: 36.5 (#207)

Coding benchmarks
BenchmarkGPT-5 NanoMistral Small 3
LMArena Coding13511246
SWE-bench Verified (bash only)34.8%—
WeirdML38.1%—
BigCodeBench Instruct—45.3%
BigCodeBench Complete—50.4%
ALE-Bench718.67—

Agentic & Tool Use Not comparable

GPT-5 Nano: 25.8 (#106), Mistral Small 3: —

Agentic & Tool Use benchmarks
BenchmarkGPT-5 NanoMistral Small 3
Terminal-Bench21.8%—
Berkeley Function Calling Leaderboard51.5%—

Reasoning Mistral Small 3 leads

GPT-5 Nano: 16.3 (#306), Mistral Small 3: 18.9 (#273)

Reasoning benchmarks
BenchmarkGPT-5 NanoMistral Small 3
Chess Puzzles27%0%
LMArena Hard Prompts13281233
Epoch Capabilities Index139.38127.07
ARC-AGI-22.6%—
Kagi LLM Benchmark62.2%—
ARC-AGI-120.7%—
Mystery Game Puzzles9%—
DTBench62.7%—
LMCA7.9%—
ForecastBench59.1—

Math GPT-5 Nano leads

GPT-5 Nano: 29.4 (#241), Mistral Small 3: 16.3 (#295)

Math benchmarks
BenchmarkGPT-5 NanoMistral Small 3
OTIS Mock AIME 2024-202581.1%6.7%
LMArena Math13171240
FrontierMath (Tiers 1-3)20%—
FrontierMath Tier 42.4%—
ProofBench12%—
Omni-MATH54.6%—
MATH Level 595.2%—
FrontierMath (Feb 2025 set)8.3%—
FrontierMath Tier 4 (v1)2.1%—

Knowledge GPT-5 Nano leads

GPT-5 Nano: 35.9 (#178), Mistral Small 3: 25.1 (#263)

Knowledge benchmarks
BenchmarkGPT-5 NanoMistral Small 3
GPQA Diamond69.4%47.3%
LMArena Expert13211202
SimpleQA Verified11.7%—
MMLU-Pro77.8%—
Confabulations—25.2%
Vectara Hallucination Rate10.5%—
GPQA (HELM)67.9%—

Multimodal Not comparable

GPT-5 Nano: 31.3 (#108), Mistral Small 3: —

Multimodal benchmarks
BenchmarkGPT-5 NanoMistral Small 3
LMArena Vision1159—
VPCT37.2%—

Multilingual GPT-5 Nano leads

GPT-5 Nano: 45.3 (#172), Mistral Small 3: 37.3 (#236)

Multilingual benchmarks
BenchmarkGPT-5 NanoMistral Small 3
LMArena Non-English13131198
LMArena Chinese13561204
LMArena German13271211
LMArena Japanese12261111
LMArena Korean12691188
LMArena Russian12961216
LMArena French—1203
LMArena Spanish1360—

Instruction Following GPT-5 Nano leads

GPT-5 Nano: 75.0 (#79), Mistral Small 3: 63.7 (#229)

Instruction Following benchmarks
BenchmarkGPT-5 NanoMistral Small 3
LMArena Instruction Following13061214
IFEval93.2%—

Long Context Mistral Small 3 leads

GPT-5 Nano: 31.3 (#281), Mistral Small 3: 37.8 (#211)

Long Context benchmarks
BenchmarkGPT-5 NanoMistral Small 3
LMArena Longer Query13121246
Fiction.LiveBench44.4%—

Writing & Preference GPT-5 Nano leads

GPT-5 Nano: 39.1 (#249), Mistral Small 3: 32.2 (#280)

Writing & Preference benchmarks
BenchmarkGPT-5 NanoMistral Small 3
LMArena Text13201234
LMArena Creative Writing12491195
EQ-Bench Creative Writing705707
LMArena Multi-Turn13111217
WildBench80.6%—

Frequently asked questions

Is GPT-5 Nano better than Mistral Small 3?

GPT-5 Nano is the stronger model overall, scoring 33.5 to 31.2 on the Noometry Index. Mistral Small 3 costs 2.4× less per token, which makes it the better buy when GPT-5 Nano's lead doesn't matter for your workload.

Which is cheaper, GPT-5 Nano or Mistral Small 3?

Mistral Small 3 is cheaper. It lists at $0.05 per million input tokens and $0.08 per million output tokens; GPT-5 Nano lists at $0.05 and $0.40.

Is GPT-5 Nano or Mistral Small 3 better for coding?

Mistral Small 3 scores higher on coding benchmarks: 36.5 versus 33.6 in the Noometry coding category.

Which has the bigger context window?

GPT-5 Nano does, with 400K tokens against 33K.

How many benchmarks do GPT-5 Nano and Mistral Small 3 share?

20 benchmarks have published results for both models. GPT-5 Nano has 49 scored results on Noometry and Mistral Small 3 has 24.

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