Model comparison

GPT-5-Codex vs Inkling-Small

Inkling-Small is the stronger model overall, scoring 46.5 to 37.9 on the Noometry Index.

Last verified . 0 shared benchmarks.

GPT-5-Codex OpenAI

37.9

Rank #192 Reported

Inkling-Small Thinking Machines Lab

46.5

Rank #63 Confirmed

Summary

  • The widest gap is in reasoning, where Inkling-Small leads 38.6 to 30.9.
  • Inkling-Small is cheaper at $0.45 / $1.20 per million input/output tokens, against $1.25 / $10 for GPT-5-Codex.
  • Inkling-Small accepts more context: 524K tokens versus 400K.
  • Inkling-Small has downloadable open weights; the other is API-only.

Side by side

GPT-5-Codex and Inkling-Small specifications
GPT-5-CodexInkling-Small
ProviderOpenAIThinking Machines Lab
Noometry Index37.946.5
Released2025-09-152026-07-15
WeightsProprietaryOpen
Context window400K524K
Max output128K1.05M
Input $ / M tokens$1.25$0.45
Output $ / M tokens$10$1.20
Results tracked333

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Category by category

Coding Inkling-Small leads

GPT-5-Codex: 42.4 (#103), Inkling-Small: 43.6 (#85)

Coding benchmarks
BenchmarkGPT-5-CodexInkling-Small
LMArena WebDev—1409
SciCode—48.7%
WeirdML54.5%—
LMArena Coding—1451

Agentic & Tool Use Not comparable

GPT-5-Codex: 31.0 (#72), Inkling-Small: —

Agentic & Tool Use benchmarks
BenchmarkGPT-5-CodexInkling-Small
Terminal-Bench44.3%—

Reasoning Inkling-Small leads

GPT-5-Codex: 30.9 (#83), Inkling-Small: 38.6 (#63)

Reasoning benchmarks
BenchmarkGPT-5-CodexInkling-Small
ARC-AGI-2—40.1%
Kagi LLM Benchmark70.3%—
ARC-AGI-1—84%
CritPt—8.3%
Chess Puzzles—18%
LMArena Hard Prompts—1423
Mystery Game Puzzles—6%
Epoch Capabilities Index—150.15

Math Not comparable

GPT-5-Codex: —, Inkling-Small: 45.1 (#77)

Math benchmarks
BenchmarkGPT-5-CodexInkling-Small
FrontierMath (Tiers 1-3)—46.3%
FrontierMath Tier 4—17.1%
OTIS Mock AIME 2024-2025—90%
ProofBench—6%
LMArena Math—1459

Knowledge Not comparable

GPT-5-Codex: —, Inkling-Small: 48.2 (#77)

Knowledge benchmarks
BenchmarkGPT-5-CodexInkling-Small
GPQA Diamond—88.5%
SimpleQA Verified—19.1%
LMArena Expert—1442

Multimodal Not comparable

GPT-5-Codex: —, Inkling-Small: 39.1 (#62)

Multimodal benchmarks
BenchmarkGPT-5-CodexInkling-Small
LMArena Vision—1235

Multilingual Not comparable

GPT-5-Codex: —, Inkling-Small: 51.7 (#104)

Multilingual benchmarks
BenchmarkGPT-5-CodexInkling-Small
LMArena Non-English—1402
LMArena Chinese—1465
LMArena French—1436
LMArena German—1405
LMArena Japanese—1405
LMArena Korean—1363
LMArena Russian—1391
LMArena Spanish—1428

Instruction Following Not comparable

GPT-5-Codex: —, Inkling-Small: 73.8 (#114)

Instruction Following benchmarks
BenchmarkGPT-5-CodexInkling-Small
LMArena Instruction Following—1399

Long Context Not comparable

GPT-5-Codex: —, Inkling-Small: 42.7 (#118)

Long Context benchmarks
BenchmarkGPT-5-CodexInkling-Small
LMArena Longer Query—1401

Writing & Preference Not comparable

GPT-5-Codex: —, Inkling-Small: 59.6 (#107)

Writing & Preference benchmarks
BenchmarkGPT-5-CodexInkling-Small
LMArena Text—1414
LMArena Creative Writing—1331
EQ-Bench Creative Writing—1491
LMArena Multi-Turn—1418

Frequently asked questions

Is GPT-5-Codex better than Inkling-Small?

Inkling-Small is the stronger model overall, scoring 46.5 to 37.9 on the Noometry Index.

Which is cheaper, GPT-5-Codex or Inkling-Small?

Inkling-Small is cheaper. It lists at $0.45 per million input tokens and $1.20 per million output tokens; GPT-5-Codex lists at $1.25 and $10.

Is GPT-5-Codex or Inkling-Small better for coding?

Inkling-Small scores higher on coding benchmarks: 43.6 versus 42.4 in the Noometry coding category.

Which has the bigger context window?

Inkling-Small does, with 524K tokens against 400K.

How many benchmarks do GPT-5-Codex and Inkling-Small share?

0 benchmarks have published results for both models. GPT-5-Codex has 3 scored results on Noometry and Inkling-Small has 33.

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