---
license: odc-by
viewer: false
task_categories:
- text-generation
pretty_name: Bolmo Training Mix (December 2025)
language:
- en
configs:
  - config_name: default
    data_files:
      - split: train
        path: data/**/*

  - config_name: cute_style_character
    data_files:
      - split: train
        path: data/cute_style_character/**/*

  - config_name: stack_edu
    data_files:
      - split: train
        path: data/stack_edu-*/**/*

  - config_name: common_crawl
    data_files:
      - split: train
        path: data/common_crawl-*/**/*

  - config_name: wikipedia
    data_files:
      - split: train
        path: data/dolma_1_7-wiki-en/**/*

  - config_name: extra_stack_edu
    data_files:
      - split: train
        path: data/extra_stack_edu/**/*

  - config_name: finemath-3plus
    data_files:
      - split: train
        path: data/finemath-3plus/**/*

  - config_name: olmocr_science_pdfs
    data_files:
      - split: train
        path: data/olmocr_science_pdfs-*/**/*

  - config_name: arxiv
    data_files:
      - split: train
        path: data/rpj-proofpile-arxiv/**/*
---

# Bolmo Mix

Data used to train **Bolmo**, the first family of competitive fully open byte-level language models (LMs).

See our technical report for details: https://allenai.org/papers/bolmo.

| Name                    | Tokens | License   |
|-------------------------|--------| ----------|
| Common Crawl            | 121.0B | ODC-BY    |
| olmOCR Science PDFs     | 19.9B  | ODC-BY    |
| StackEdu                | 26.3B  | ODC-BY    |
| FineMath 3+             | 4.1B   | ODC-BY    |
| arXiv                   | 1.3B   | ODC-BY    |
| Wikipedia & Wikibooks   | 64.6M  | ODC-BY    |
| Character Understanding | 75.5M  | ODC-BY    |
| Total                   | **172.7B** |       |

Bolmo models are trained for less than one epoch (~39.3B tokens) on this mix.

## Licensing Information

Bolmo Mix is licensed under the Open Data Commons Attribution License v1.0 (ODC-By). It is intended for research and educational use. For more information, please see our [Responsible Use Guidelines](https://allenai.org/responsible-use).

## Citation

```bibtex
@misc{bolmo,
      title={Bolmo: Byteifying the Next Generation of Language Models}, 
      author={Benjamin Minixhofer and Tyler Murray and Tomasz Limisiewicz and Anna Korhonen and Luke Zettlemoyer and Noah A. Smith and Edoardo M. Ponti and Luca Soldaini and Valentin Hofmann},
      year={2025},
      eprint={2512.15586},
      archivePrefix={arXiv},
      primaryClass={cs.CL},
      url={https://arxiv.org/abs/2512.15586}, 
}
```