Spirax
Spirax is a display font in 1 weight. Its lowercase letters are 6% narrower than the typical display font. Last updated 10 September 2025.
Editing a PDF that uses Spirax
Most PDFs embed only the letters they already use. Type a new letter and many editors either refuse or swap in a different font. MythosPDF recognises Spirax from the widths stored in your PDF, loads the complete open font, and sets your new text in Spirax itself. The rest of the page is carried over untouched.
Measured metrics
| Average lowercase letter width | 492.3 units per 1000 em |
|---|---|
| Average capital letter width | 672.3 units per 1000 em |
| Word space | 204 units per 1000 em |
| Digits | proportional (digit widths differ) |
| Spacing | proportional |
| Width of i compared with m | 27% |
| Printable ASCII characters covered | 94 of 94 |
| Category | Display |
Weights and styles
Open fonts closest to Spirax
Measured on every printable character both fonts contain. A smaller difference means the same words take the same space, so lines break in the same places.
- Alike Regularloosely similar widths (43.1 units)
- Alike Angular Regularloosely similar widths (43.1 units)
- Cambo Regularloosely similar widths (43.9 units)
- Vidaloka Regularloosely similar widths (44.1 units)
- Petrona Regularloosely similar widths (44.2 units)
- Pitagon Serif Regularloosely similar widths (44.2 units)
- El Messiri Regularloosely similar widths (44.8 units)
- Philosopher Regularloosely similar widths (45.9 units)
Compare Spirax
Questions people ask
+Can I edit a PDF that uses Spirax?
Yes. Drop the PDF into MythosPDF and click the text. New letters are set in Spirax itself, loaded from the open font, so the edit matches the rest of the page.
+Is Spirax free to use?
Spirax is released under the SIL Open Font License 1.1, an open licence that allows free use in documents, including commercial ones. Check the licence text for your exact use.
+Which font is closest to Spirax?
By measured letter widths, Alike is the closest match among open fonts (a mean difference of 43.1 units per 1000 em). Text set in one takes almost the same space in the other.
+Which languages does Spirax support?
It includes these character sets: Latin.
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