# Fonts Like IBM Plex Serif

12 open fonts whose letters are closest to IBM Plex Serif, ranked by a glyph comparison. All free for commercial use.

## Quick Answer

The closest open font to IBM Plex Serif is Charis SIL (similarity 79), then DejaVu Math and Source Serif 4. Charis SIL is released under the SIL Open Font License 1.1 and is free for commercial use.

## Ranked Open Lookalikes (12 Fonts)

| Rank | Font | Similarity Score | Licence | Details |
| :--- | :--- | :--- | :--- | :--- |
| #1 | **Charis SIL** | 79 / 100 | OFL-1.1 | [/fonts/charis-sil/](/fonts/charis-sil.md) |
| #2 | **DejaVu Math** | 78 / 100 | OFL-1.1 | [/fonts/dejavu-math/](/fonts/dejavu-math.md) |
| #3 | **Source Serif 4** | 77 / 100 | OFL-1.1 | [/fonts/source-serif-4/](/fonts/source-serif-4.md) |
| #4 | **Frank Ruhl Libre** | 77 / 100 | OFL-1.1 | [/fonts/frank-ruhl-libre/](/fonts/frank-ruhl-libre.md) |
| #5 | **Domine** | 76 / 100 | OFL-1.1 | [/fonts/domine/](/fonts/domine.md) |
| #6 | **Brawler** | 76 / 100 | OFL-1.1 | [/fonts/brawler/](/fonts/brawler.md) |
| #7 | **Noto Serif Hentaigana** | 75 / 100 | OFL-1.1 | [/fonts/noto-serif-hentaigana/](/fonts/noto-serif-hentaigana.md) |
| #8 | **PT Serif Caption** | 75 / 100 | OFL-1.1 | [/fonts/pt-serif-caption/](/fonts/pt-serif-caption.md) |
| #9 | **Faustina** | 74 / 100 | OFL-1.1 | [/fonts/faustina/](/fonts/faustina.md) |
| #10 | **Noto Serif** | 74 / 100 | OFL-1.1 | [/fonts/noto-serif/](/fonts/noto-serif.md) |
| #11 | **IBM Plex Sans** | 74 / 100 | OFL-1.1 | [/fonts/ibm-plex-sans/](/fonts/ibm-plex-sans.md) |
| #12 | **Roboto Slab** | 73 / 100 | Apache-2.0 | [/fonts/roboto-slab/](/fonts/roboto-slab.md) |

## Other Scripts With Similar Latin Letters

- **Suwannaphum** (Khmr): Similarity 76, licence OFL-1.1 - [/fonts/suwannaphum/](/fonts/suwannaphum.md)
- **Abyssinica SIL** (Ethi): Similarity 75, licence OFL-1.1 - [/fonts/abyssinica-sil/](/fonts/abyssinica-sil.md)
- **Annapurna SIL** (Deva): Similarity 75, licence OFL-1.1 - [/fonts/annapurna-sil/](/fonts/annapurna-sil.md)

## Scoring Method

62 letters and digits (A-Z a-z 0-9) rendered at 160px cap height on a 32x32 grid with 3px gaussian blur, combined with edge-orientation texture (15% weight). Scores are normalized so that 0 represents an average pair of fonts across the 1571 compared fonts, and 100 represents identical letter shapes. Computed on 2026-10-22 using glyph-shape + edge-texture v2.

## Machine API

JSON representation available at [/api/fonts-like/ibm-plex-serif.json](/api/fonts-like/ibm-plex-serif.json).