OTF vs. TTF: Which Font Type Should You Use?

OpenType Font (OTF) and TrueType Font (TTF) are two different file formats for representing fonts on computers. But if you want to know which format to choose, there isn’t an easy answer. Those articles on the Internet saying OTF is the best are misleading and don’t show how font specifications work. We did our research so that you can learn the truth about the technology behind OTF and TTF, how they’re different, and how they aren’t.

Helpful tip: download free fonts from Google Fonts to your computer.

History

Apple released TrueType in 1991 to avoid paying licensing fees for the rights to use Adobe’s Postscript-based Type 1 fonts. To make it more widely available, Apple licensed TrueType to Microsoft for free.

Meanwhile, Microsoft started working on OpenType in 1994. Adobe joined their development efforts in 1996. The newer OpenType got features of both Apple’s TrueType and Adobe’s Type 1 fonts, plus some new ones, essentially becoming a successor to both.

These days, almost all fonts are OpenType-based with very few exceptions.

Does File Extension Matter?

Knowing that OpenType is the more modern choice, should you always choose an .OTF file over a .TTF file? No! This is a common misconception. You can’t determine the font technology from the file extension alone.

OpenType fonts can have either an .OTF or a .TTF extension, as the OpenType format can use one of two glyph outline formats: TrueType or Compact Font Format (CFF). OpenType fonts with TrueType outlines can have the .TTF extension, while those with CFF outlines use the .OTF extension.

In short, both .OTF and .TTF file extensions are equally good choices if you want the latest font features.

Good to know: if you are seeing pixelated or corrupted fonts in Windows, we show you how to fix it.

OpenType Features

While the file extensions often don’t matter, there are still differences between the underlying font specifications. OpenType is the ideal format, as it’s more modern and includes more features than TrueType, and it keeps improving over time with updates. There’s just not much choice in the matter, as almost every font you encounter on a computer will be an OpenType font!

Glyph Substitutions

OpenType has glyph substitutions, which means a single character (such as the lowercase letter “o”) can be represented by multiple slightly distinct symbols, or glyphs, depending on the context.

This feature also allows for greater support for different languages. In languages like Arabic, where a character must look different depending on its position in a word, glyph substitutions are a must-have.

Variable Fonts

Typefaces usually come with a few predefined weights that decide the thickness of each character, such as light, regular, and bold. But this limits you to only four or five different weights per typeface, and if you want a weight that falls in between the predefined weights – thicker than light, but thinner than regular – you’d be out of luck.

This changes with OpenType variable fonts. New fonts with this feature can have weights set to any number between 1 and 1000, meaning you have hundreds of weights at your disposal and can pick the exact thickness you want.

Not every OpenType font comes with this feature, so if you want to use it, look for fonts that are described as being “variable” or that have “variable” in the name. Additionally, different variable fonts may have different ranges for the weights you can set: many have a minimum weight of 100 and a maximum of 900, which is far different than the full 1 to 1000 range.

Tip: need to find out the fonts used in an image? We have the means to do it.

Ligatures

Another font feature offered by the OpenType standard is ligatures. A ligature is a special symbol that combines two or more characters. Usually, the multiple characters in ligatures appear visually joined together with no space in between them. A ligature example relevant to programmers is that the logical operator for “not equal to” (!==), made of 3 characters, can become a single symbol with a diagonal line cutting across it. This can make disparate symbols or letters look naturally combined, something only otherwise possible if they were handwritten.

Using this feature can enhance the visual appeal and readability of your text. But it isn’t available in all OpenType fonts, so you need to look for one that explicitly supports ligatures. Additionally, check to see if your text program includes support for ligatures. You may need to enable ligatures in the settings.

Operating System Compatibility

OpenType fonts (which, as mentioned earlier can have either .TTF or .OTF file extensions) are compatible with macOS, Windows, and Linux systems. Again, because almost every font uses OpenType under the hood, you shouldn’t have any issues installing most fonts on any OS.

If you encounter the rare pure TrueType font, your next step should be to find an updated OpenType version of that font. This should not happen much anymore, so if this happens to you, let us know where you were able to find such a relic from the past!

To install fonts, see these guides in Windows, Android, Linux and iOS.

Converting Font Formats

What happens if you try to use a font, but your system says it’s the wrong format? While this should rarely happen for reasons discussed in this article, it’s still good to know how to convert between .TTF and .OTF fonts.

We recommend using CloudConvert, a free website, to convert fonts. It’s easy – simply upload your font, choose the format you want, and download it.

Alternatively, check out our article on converting fonts to .TTF in Ubuntu – it involves using FontForge.

Frequently Asked Questions

Image credit: Pexels. All graphics and screenshots by Brandon Li.