Fonts like Spline Sans Mono
12 open fonts whose letters are closest to Spline Sans Mono, ranked by a glyph comparison. All free for commercial use.
Quick answer
The closest open font to Spline Sans Mono is IBM Plex Mono (similarity 84), then Google Sans Code and iA Writer Mono. IBM Plex Mono is released under the SIL Open Font License 1.1 and is free for commercial use.
Side-by-side comparison
Top lookalikes compared at the same size Sphinx of black quartz, judge my vow
Sphinx of black quartz, judge my vow
Sphinx of black quartz, judge my vow
Sphinx of black quartz, judge my vow
Top lookalikes: licence permissions
Commercial rights side by sideIBM Plex MonoOFL-1.1
Commercial workAllowed
Logo or wordmarkAllowed
WebsiteAllowed, with conditions
App or gameAllowed, with conditions
Modify the fontAllowed, with conditions
Share the font fileAllowed, with conditions
Sell the font fileNot allowed
No credit needed in your workAllowed
Google Sans CodeOFL-1.1
Commercial workAllowed
Logo or wordmarkAllowed
WebsiteAllowed, with conditions
App or gameAllowed, with conditions
Modify the fontAllowed, with conditions
Share the font fileAllowed, with conditions
Sell the font fileNot allowed
No credit needed in your workAllowed
iA Writer MonoOFL-1.1
Commercial workAllowed
Logo or wordmarkAllowed
WebsiteAllowed, with conditions
App or gameAllowed, with conditions
Modify the fontAllowed, with conditions
Share the font fileAllowed, with conditions
Sell the font fileNot allowed
No credit needed in your workAllowed
All 12 open lookalikes, ranked
Comparison based on letter shape and edge texture#1
IBM Plex Mono OFL-1.1
Similarity 84 — 100 = identical letters, 0 = an average pair
Sphinx of black quartz, judge my vow
#2
Google Sans Code OFL-1.1
Similarity 82 — 100 = identical letters, 0 = an average pair
Sphinx of black quartz, judge my vow
#3
iA Writer Mono OFL-1.1
Similarity 82 — 100 = identical letters, 0 = an average pair
Sphinx of black quartz, judge my vow
#4
Roboto Mono OFL-1.1
Similarity 81 — 100 = identical letters, 0 = an average pair
Sphinx of black quartz, judge my vow
#5
Chivo Mono OFL-1.1
Similarity 81 — 100 = identical letters, 0 = an average pair
Sphinx of black quartz, judge my vow
#6
Fira Code OFL-1.1
Similarity 81 — 100 = identical letters, 0 = an average pair
Sphinx of black quartz, judge my vow
#7
Commit Mono OFL-1.1
Similarity 81 — 100 = identical letters, 0 = an average pair
Sphinx of black quartz, judge my vow
#8
Geist Mono OFL-1.1
Similarity 80 — 100 = identical letters, 0 = an average pair
Sphinx of black quartz, judge my vow
#9
Martian Mono OFL-1.1
Similarity 80 — 100 = identical letters, 0 = an average pair
Sphinx of black quartz, judge my vow
#10
Monaspace Neon OFL-1.1
Similarity 79 — 100 = identical letters, 0 = an average pair
Sphinx of black quartz, judge my vow
#11
DejaVu Mono OFL-1.1
Similarity 78 — 100 = identical letters, 0 = an average pair
Sphinx of black quartz, judge my vow
#12
Noto Sans Mono OFL-1.1
Similarity 78 — 100 = identical letters, 0 = an average pair
Sphinx of black quartz, judge my vow
How the similarity score works
Each score is calculated by comparing 62 letters and digits (A-Z a-z 0-9) rendered at a 160px cap height on a 32×32 grid with 3px gaussian blur, combined with edge-orientation texture (weighted at 15%).
Scores are normalized on a standardized scale: 100 represents identical letterforms, and 0 represents an average pair among the 1571 fonts compared.