Text / LLM / Model

OpenAI o1

Organisation
OpenAI
Family
o-series
Released
2024-12-05 (Date of the o1 System Card ('December 5, 2024'); o1-preview was released earlier (snapshot o1-preview-2024-09-12))
Training cutoff
2023-10-01
Evidence
“Oct 01, 2023 knowledge cutoff”
developers.openai.com · website · Model page header · retrieved 2026-10-15
Checkpoints
o1-2024-12-17, o1-preview-2024-09-12
Weights
Closed · proprietary
Links

Training data disclosure: Vague

Level determined for 13% of benchmark cells.

“The two models were pre-trained on diverse datasets, including a mix of publicly available data, proprietary data accessed through partnerships, and custom datasets developed in-house”
arxiv.org · model card · Section 2 · retrieved 2026-10-15

Other declared training data

Benchmark cells

Classic LLM benchmarks

Unknown MMLU (Measuring Massive Multitask Language Understanding) · training data not disclosed in enough detail

Unknown GSM8K (Grade School Math 8K) · training data not disclosed in enough detail

Unknown MATH (Mathematics Aptitude Test of Heuristics) · training data not disclosed in enough detail

Unknown HumanEval · training data not disclosed in enough detail

Unknown ARC-Challenge (AI2 Reasoning Challenge, Challenge Set) · training data not disclosed in enough detail

Unknown HellaSwag · training data not disclosed in enough detail

Unknown TruthfulQA · training data not disclosed in enough detail

Unknown WinoGrande · training data not disclosed in enough detail

Multimodal LLM benchmarks

Unknown MMMU (Massive Multi-discipline Multimodal Understanding and Reasoning) · training data not disclosed in enough detail

Unknown MMMU-Pro · training data not disclosed in enough detail

Unknown MathVista · training data not disclosed in enough detail

Unknown ChartQA · training data not disclosed in enough detail

Unknown DocVQA · training data not disclosed in enough detail

Unknown AI2D (AI2 Diagrams) · training data not disclosed in enough detail

Not seen CharXiv · its test items were published from 2024-06-26, after the model's stated training-data cutoff (2023-10-01)

Evidence (3)
“Oct 01, 2023 knowledge cutoff”
developers.openai.com · website · Model page header · retrieved 2026-10-15
“arXiv:2406.18521v1 [cs.CL] 26 Jun 2024”
arxiv.org · paper · arXiv v1 header · retrieved 2026-10-15
“we release all QA pairs for the validation set and keep the answers to the test set private to prevent data leakage.”
arxiv.org · paper · Section 3, footnote 4 · retrieved 2026-10-15

Recent LLM benchmarks

Unknown GPQA Diamond · training data not disclosed in enough detail

Unknown MMLU-Pro · training data not disclosed in enough detail

Unknown LiveCodeBench (code generation, release_v6) · training data not disclosed in enough detail

Unknown SWE-bench Verified · training data not disclosed in enough detail

Not seen AIME 2024 · its test items were published from 2024-01-31, after the model's stated training-data cutoff (2023-10-01)

Evidence (4)
“Oct 01, 2023 knowledge cutoff”
developers.openai.com · website · Model page header · retrieved 2026-10-15
“2024 AIME I problems and solutions. The test was held on Wednesday, January 31 – Thursday, February 1, 2024.”
web.archive.org · website · retrieved 2026-10-15
“AIME I (main AIME competition date): Thursday, Feb. 1, 2024 between 1:30 pm ET and 5:30 pm ET.”
web.archive.org · website · retrieved 2026-10-15
“AIME II (alternate AIME competition date): Wednesday, Feb. 7, 2024 between 1:30 pm ET and 5:30 pm ET.”
web.archive.org · website · retrieved 2026-10-15

Not seen AIME 2025 · its test items were published from 2025-02-06, after the model's stated training-data cutoff (2023-10-01)

Evidence (3)
“Oct 01, 2023 knowledge cutoff”
developers.openai.com · website · Model page header · retrieved 2026-10-15
“2025 AIME I problems and solutions. The test was held on Thursday, February 6, 2025.”
web.archive.org · website · retrieved 2026-10-15
“This year the AIME I will take place on February 6, 2025, while the alternate AIME II will take place on February 12, 2025.”
maa.org · website · retrieved 2026-10-15

Unknown MATH-500 · training data not disclosed in enough detail

Notes

System card covers o1 and o1-mini. No contamination or decontamination statement found. The card notes an improved o1 launched on December 17 (snapshot o1-2024-12-17) that postdates the card. Accepts image input: “Modalities Text Input and output Image Input only”

Sources