---
title: Font size
framework: quicktime-file-format
role: symbol
role_heading: Data field
path: quicktime-file-format/subtitle_sample_description/font_size
---

# Font size

An 8-bit value for the font size, expressed in points.

## Overview

Overview The value should always be 0.05 multiplied by the video track header height. For example, if the video track header is 720 points in height, this should be 36 (points). This size should be used in the default style record and in any per-sample style records. If a subtitle does not fit in the text box, the subtitle media handler may choose to shrink the font size so that the subtitle fits.

## See Also

### Data fields

- [Display flags](quicktime-file-format/subtitle_sample_description/display_flags.md)
- [Reserved](quicktime-file-format/subtitle_sample_description/reserved.md)
- [Reserved](quicktime-file-format/subtitle_sample_description/reserved2.md)
- [Reserved](quicktime-file-format/subtitle_sample_description/reserved3.md)
- [Default text box](quicktime-file-format/subtitle_sample_description/default_text_box.md)
- [Reserved](quicktime-file-format/subtitle_sample_description/reserved4.md)
- [Font identifier](quicktime-file-format/subtitle_sample_description/font_identifier.md)
- [Font face](quicktime-file-format/subtitle_sample_description/font_face.md)
- [Foreground color](quicktime-file-format/subtitle_sample_description/foreground_color.md)
- [Font table](quicktime-file-format/subtitle_sample_description/font_table.md)