Model comparison
GPT-5.1-Codex vs Inkling-Small
Inkling-Small is the stronger model overall, scoring 46.5 to 38.6 on the Noometry Index.
Last verified . 2 shared benchmarks.
Summary
- They share 2 benchmarks with published results for both. GPT-5.1-Codex scores higher in 0 categories and Inkling-Small in 2 categories; 2 gaps are clear of the uncertainty.
- The widest gap is in math, where Inkling-Small leads 45.1 to 30.3.
- Inkling-Small is cheaper at $0.45 / $1.20 per million input/output tokens, against $1.25 / $10 for GPT-5.1-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-5.1-Codex | Inkling-Small | |
|---|---|---|
| Provider | OpenAI | Thinking Machines Lab |
| Noometry Index | 38.6 | 46.5 |
| Released | 2025-11-12 | 2026-07-15 |
| Weights | Proprietary | Open |
| Context window | 400K | 524K |
| Max output | 128K | 1.05M |
| Input $ / M tokens | $1.25 | $0.45 |
| Output $ / M tokens | $10 | $1.20 |
| Results tracked | 6 | 33 |
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Category by category
Coding Inkling-Small leads
GPT-5.1-Codex: 41.9 (#116), Inkling-Small: 43.6 (#85)
| Benchmark | GPT-5.1-Codex | Inkling-Small |
|---|---|---|
| LMArena WebDev | 1337 | 1409 |
| SWE-bench Verified (bash only) | 66% | — |
| SciCode | — | 48.7% |
| LMArena Coding | — | 1451 |
| ALE-Bench | 1,245 | — |
Agentic & Tool Use Not comparable
GPT-5.1-Codex: 38.0 (#33), Inkling-Small: —
| Benchmark | GPT-5.1-Codex | Inkling-Small |
|---|---|---|
| Terminal-Bench | 60.4% | — |
| METR Time Horizons | 70.8% | — |
Reasoning Not comparable
GPT-5.1-Codex: —, Inkling-Small: 38.6 (#63)
| Benchmark | GPT-5.1-Codex | Inkling-Small |
|---|---|---|
| ARC-AGI-2 | — | 40.1% |
| ARC-AGI-1 | — | 84% |
| CritPt | — | 8.3% |
| Chess Puzzles | — | 18% |
| LMArena Hard Prompts | — | 1423 |
| Mystery Game Puzzles | — | 6% |
| Epoch Capabilities Index | — | 150.15 |
Math Inkling-Small leads
GPT-5.1-Codex: 30.3 (#235), Inkling-Small: 45.1 (#77)
| Benchmark | GPT-5.1-Codex | Inkling-Small |
|---|---|---|
| ProofBench | 9% | 6% |
| FrontierMath (Tiers 1-3) | — | 46.3% |
| FrontierMath Tier 4 | — | 17.1% |
| OTIS Mock AIME 2024-2025 | — | 90% |
| LMArena Math | — | 1459 |
Knowledge Not comparable
GPT-5.1-Codex: —, Inkling-Small: 48.2 (#77)
| Benchmark | GPT-5.1-Codex | Inkling-Small |
|---|---|---|
| GPQA Diamond | — | 88.5% |
| SimpleQA Verified | — | 19.1% |
| LMArena Expert | — | 1442 |
Multimodal Not comparable
GPT-5.1-Codex: —, Inkling-Small: 39.1 (#62)
| Benchmark | GPT-5.1-Codex | Inkling-Small |
|---|---|---|
| LMArena Vision | — | 1235 |
Multilingual Not comparable
GPT-5.1-Codex: —, Inkling-Small: 51.7 (#104)
| Benchmark | GPT-5.1-Codex | Inkling-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-5.1-Codex: —, Inkling-Small: 73.8 (#114)
| Benchmark | GPT-5.1-Codex | Inkling-Small |
|---|---|---|
| LMArena Instruction Following | — | 1399 |
Long Context Not comparable
GPT-5.1-Codex: —, Inkling-Small: 42.7 (#118)
| Benchmark | GPT-5.1-Codex | Inkling-Small |
|---|---|---|
| LMArena Longer Query | — | 1401 |
Writing & Preference Not comparable
GPT-5.1-Codex: —, Inkling-Small: 59.6 (#107)
| Benchmark | GPT-5.1-Codex | Inkling-Small |
|---|---|---|
| LMArena Text | — | 1414 |
| LMArena Creative Writing | — | 1331 |
| EQ-Bench Creative Writing | — | 1491 |
| LMArena Multi-Turn | — | 1418 |
Frequently asked questions
Is GPT-5.1-Codex better than Inkling-Small?
Inkling-Small is the stronger model overall, scoring 46.5 to 38.6 on the Noometry Index.
Which is cheaper, GPT-5.1-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-5.1-Codex lists at $1.25 and $10.
Is GPT-5.1-Codex or Inkling-Small better for coding?
Inkling-Small scores higher on coding benchmarks: 43.6 versus 41.9 in the Noometry coding category.
Which has the bigger context window?
Inkling-Small does, with 524K tokens against 400K.
How many benchmarks do GPT-5.1-Codex and Inkling-Small share?
2 benchmarks have published results for both models. GPT-5.1-Codex has 6 scored results on Noometry and Inkling-Small has 33.