What is SFD?

Spline Font Database (SFD) is the native project file format for FontForge, an open-source font editor for font design.

What is UFO?

UFO (Unified Font Object) is an open, XML-based font source format used by professional font editors for collaborative font development.

When Should You Use SFD vs UFO?

Use SFD When...

Reach for SFD when your priority is font design and editing, fontforge projects — its uncompromising quality ensures every detail is preserved.

Use UFO When...

Reach for UFO when your priority is font design and editing, collaborative font development, glyphs/robofont — its uncompromising quality ensures every detail is preserved.

SFD vs UFO: Key Differences

•SFD and UFO diverge on compression: lossless compression for the source, lossless compression for the target.
•Since both SFD and UFO use lossless compression, the quality characteristics are comparable — differences in file size come down to how efficiently each format implements compression.
•How transparency is handled: UFO supports transparency, so alpha information is preserved during conversion.
•SFD files are typically Larger than production fonts due to editing metadata while UFO files range 100KB to 10MB+ depending on glyph count
•Primary audience: SFD is built for font design and editing, fontforge projects scenarios, while UFO focuses on font design and editing, collaborative font development, glyphs/robofont — pick the format that matches your output requirement.

Advantages of SFD

✓SFD uses lossless compression tailored for Font design and editing, FontForge projects.
✓SFD is supported natively on virtually every device, browser, and operating system.
✓SFD files are bit-for-bit perfect, preserving every pixel and sample for professional work.
✓SFD integrates seamlessly with all major creative tools and workflows.

Advantages of UFO

✓UFO uses lossless compression tailored for Font design and editing, collaborative font development, Glyphs/RoboFont.
✓UFO is supported natively on virtually every device, browser, and operating system.
✓UFO files are bit-for-bit perfect, preserving every pixel and sample for professional work.
✓UFO integrates seamlessly with all major creative tools and workflows.

Common Use Cases for SFD to UFO Conversion

Video subtitles
Game UI typography
Website typography
Brand identity
Print design
Mobile apps

Industry Applications

Book PublishingMobile App DevelopmentWeb DesignTypographyGraphic DesignDesktop Publishing

Best Practices for SFD to UFO Conversion

→Before converting SFD to UFO, review the font license — some licenses restrict format conversion
→Check hinting data after conversion: UFO may handle TrueType hinting differently than SFD
→Verify that all character sets (Latin, Cyrillic, CJK, etc.) survived the conversion intact
→Test the converted font in both a browser and a desktop application
→Keep the original font file in case the conversion alters spacing metrics

Troubleshooting SFD to UFO Conversion

!UFO font doesn't render correctly → check if UFO supports all glyphs present in SFD
!Licensing restrictions after SFD to UFO conversion → verify the font license allows format conversion
!Hinting data lost converting SFD to UFO → some font formats like UFO may not preserve TrueType hinting
!Special characters missing from converted UFO → font subsetting may have removed unused glyphs

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Convert to UFO →Convert from SFD →

Convert SFD to UFO Online - Free & Fast

Convert SFD files to UFO online for free. High-quality conversion with no registration required.

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.sfd,.SFD (max 100MB)

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About SFD and UFO

SFD

SFD (SFD fonts) - Spline Font Database, FontForge native font editing format. Best for font design and editing, fontforge projects.

UFO

UFO (UFO) - Unified Font Object, XML-based source format for font design and editing. Ideal for font design and editing, collaborative font development, glyphs/robofont.

Format Comparison

CompressionLossless → Lossless

TransparencySupported

Use CaseConvert from font design and editing, fontforge projects to font design and editing, collaborative font development, glyphs/robofont

File Size~100KB to 10MB+ depending on glyph count after conversion

FAQs

Is converting SFD to UFO free?

Yes, GoConvertFile offers free conversion of SFD to UFO for files up to 100MB. No registration required.

How long does it take to convert SFD to UFO?

Most SFD to UFO conversions complete within seconds for standard-sized files. Larger files may take longer depending on the conversion complexity.

What is UFO best used for?

UFO is ideal for font design and editing, collaborative font development, glyphs/robofont. Unified Font Object, XML-based source format for font design and editing

What file size should I expect after converting SFD to UFO?

File size after SFD to UFO conversion depends on the content complexity and quality settings. Both formats use similar compression approaches so sizes are comparable.

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