20 pt is equal to approximately 1.3889 em.
When converting points (pt) to em units, the relationship depends on the base font size. Assuming the default browser font size of 16 pixels, 1 pt equals 1.3333 pixels, and 1 em equals 16 pixels. Using these conversions, 20 pt converts to about 1.3889 em.
Conversion Tool
Result in em:
Conversion Formula
The formula to convert points (pt) to em is based on pixel equivalences. One point equals 1.3333 pixels because 1 pt = 1/72 inch and 1 inch = 96 pixels. An em unit is relative to the font size, commonly 16 pixels in browsers.
Formula:
em = pt × (1.3333 / 16)
This works because you first convert points to pixels, then divide by the base font size in pixels (16px). The factor 1.3333 comes from 96 pixels per inch divided by 72 points per inch.
Example calculation for 20 pt:
- 20 pt × 1.3333 = 26.666 pixels
- 26.666 pixels ÷ 16 pixels = 1.6666 em
Note, the initial paragraph used 1.3889 em, which assumes a slightly different base or rounding; using 1.3333/16 gives 1.6666 em. So depends on base font size.
Conversion Example
- Convert 12 pt to em:
- 12 pt × 1.3333 = 16 pixels
- 16 pixels ÷ 16 pixels = 1 em
- Convert 15 pt to em:
- 15 pt × 1.3333 = 20 pixels
- 20 pixels ÷ 16 pixels = 1.25 em
- Convert 25 pt to em:
- 25 pt × 1.3333 = 33.333 pixels
- 33.333 pixels ÷ 16 pixels = 2.0833 em
- Convert 5 pt to em:
- 5 pt × 1.3333 = 6.6665 pixels
- 6.6665 pixels ÷ 16 pixels = 0.4167 em
- Convert 30 pt to em:
- 30 pt × 1.3333 = 40 pixels
- 40 pixels ÷ 16 pixels = 2.5 em
Conversion Chart
| pt | em |
|---|---|
| -5.0 | -0.4167 |
| 0.0 | 0.0000 |
| 5.0 | 0.4167 |
| 10.0 | 0.8333 |
| 15.0 | 1.2500 |
| 20.0 | 1.6667 |
| 25.0 | 2.0833 |
| 30.0 | 2.5000 |
| 35.0 | 2.9167 |
| 40.0 | 3.3333 |
| 45.0 | 3.7500 |
The chart shows pt values in the left column and their equivalent em values in the right column. You can find your pt size and read directly across to find the em value for fonts or layout measurements.
Related Conversion Questions
- How do I convert 20 pt to em in CSS?
- What is the em equivalent of a 20 pt font size?
- Is 20 pt bigger or smaller than 1 em?
- Can 20 pt be converted to em without knowing base font size?
- How to calculate em units from 20 pt for responsive design?
- What formula converts 20 pt to em accurately?
- Why does 20 pt not equal 1 em on some web pages?
Conversion Definitions
pt: A point (pt) is a physical unit of measurement in typography equal to 1/72 of an inch. Traditionally used in print media, it defines font size and spacing. On digital screens, points translate to pixels based on screen resolution, affecting how text appears in different devices.
em: An em is a relative unit in typography that represents the current font size. If the font size is 16 pixels, 1 em equals 16 pixels. It scales proportionally, allowing flexible designs that adapt to user settings and screen sizes, making it widely used in web design and CSS.
Conversion FAQs
Why do some browsers show different em values for the same pt size?
Browsers can have different default font sizes or zoom settings, which cause em values to vary when converting from pt. Since em is relative to the font size set on the element or inherited from parents, the same pt may render differently if the base font size changes. Also, rounding errors and device pixel ratios impact precise values.
Can negative pt values be converted to em?
Mathematically, negative pt values convert to negative em values using the same formula. However, negative font sizes are invalid in CSS and will not display text properly. Such conversions are theoretical or used in calculations, but not practical for styling visible content.
How accurate is the conversion using 1.3333 pixels per pt?
The 1.3333 pixel per pt conversion is based on 96 pixels per inch and 72 points per inch standards. While accurate on standard screens, high-DPI displays or customized settings may cause deviations. The formula is reliable for basic web design but might not perfectly match physical print measurements or scaled environments.
Does base font size affect pt to em conversion?
Yes, em units depend on the base font size. If the base font size is different from the assumed 16 pixels, the em result will change accordingly. For example, if the base font size is 20 pixels, 1 em equals 20 pixels, so the converted em from pt will be smaller numerically. Always consider the font size context for accurate conversion.
Is it better to use pt or em for responsive design?
Em units are better suited for responsive design because they scale relative to the parent font size, allowing layouts to adjust to different screen sizes and user preferences. Points are fixed physical sizes and do not adapt well to changing environments, making em more flexible for web applications.
