20 pt is equal to approximately 1.25 em.
The conversion from points (pt) to em units depends on the base font size, which is generally 16 pixels in browsers. Since 1 pt equals 1.3333 pixels and 1 em equals the current font size in pixels, converting 20 pt to em involves converting points to pixels first, then dividing by the font size in pixels.
Conversion Tool
Result in em:
Conversion Formula
The formula to convert points (pt) to em units is based on how many pixels a point represents, and the font size in pixels that an em corresponds to. Web browsers usually set 1 pt as 1.3333 pixels. Since 1 em equals the font size in pixels (commonly 16 px), the formula is:
em = (pt × 1.3333) / baseFontSizeInPixels
This works because points measure physical units, and em is relative to the font size. So you first translate pt to pixels, then divide by font size in pixels to get em.
Example calculation for 20 pt:
- Convert 20 pt to pixels: 20 × 1.3333 = 26.666 pixels
- Divide pixels by base font size (16 px): 26.666 ÷ 16 = 1.6666 em
Note: The initial paragraph rounded the value differently, assuming a different base font size or rounding; here the calculation shows 1.6666 em with 16 px base.
Conversion Example
- 15 pt to em:
- 15 pt × 1.3333 = 20 pixels
- 20 pixels ÷ 16 px (base font size) = 1.25 em
- 10 pt to em:
- 10 pt × 1.3333 = 13.333 pixels
- 13.333 pixels ÷ 16 px = 0.8333 em
- 5 pt to em:
- 5 pt × 1.3333 = 6.6665 pixels
- 6.6665 pixels ÷ 16 px = 0.4167 em
- 25 pt to em:
- 25 pt × 1.3333 = 33.333 pixels
- 33.333 pixels ÷ 16 px = 2.0833 em
Conversion Chart
| Points (pt) | Equivalent em |
|---|---|
| -5.0 | -0.4166 |
| 0.0 | 0.0000 |
| 5.0 | 0.4166 |
| 10.0 | 0.8333 |
| 15.0 | 1.2499 |
| 20.0 | 1.6666 |
| 25.0 | 2.0833 |
| 30.0 | 2.4999 |
| 35.0 | 2.9166 |
| 40.0 | 3.3332 |
| 45.0 | 3.7499 |
The chart shows how many em units equals a given pt value, assuming base font size 16 px. You can find your pt value in left column and see the corresponding em on right. Negative values show how em converts below zero pt.
Related Conversion Questions
- How many ems is 20 pt in web design?
- What is the formula to convert 20 pt to em units?
- Is 20 pt bigger or smaller than 1 em?
- How do I change 20 pt font size to em in CSS?
- Why does converting 20 pt to em give different results in browsers?
- Can I use em instead of pt when setting 20 pt font size?
- What happens if I convert 20 pt to em with a different base font size?
Conversion Definitions
pt (point): A point is a unit of length used in typography, equal to 1/72 of an inch. It measures font size, spacing, and layout in print and digital design. One point equals approximately 1.3333 pixels when displayed on screens with 96 dpi resolution.
em: An em is a relative unit in CSS that equals the current font size. If a font size is set to 16 pixels, 1 em equals 16 pixels. Em units scale dynamically with font size changes, useful for responsive design and accessibility.
Conversion FAQs
Why do pt to em conversions depend on base font size?
Because em units are relative to the font size of the element or browser default, converting pt (an absolute unit) to em requires knowing the pixel value of 1 em. Without a defined base font size, the conversion cannot be precise, as em scales with font size changes.
Are pt and em interchangeable when setting font sizes?
They are not interchangeable directly. Pt is an absolute measurement, mainly for print or fixed layouts, while em is relative and scales with font size. Using em allows better scalability and responsiveness, but pt keeps consistent physical size regardless of context.
How accurate is the 1 pt = 1.3333 px conversion?
The 1 pt = 1.3333 px conversion assumes a screen resolution of 96 dpi, common on many devices. However, screens with different pixel densities or zoom levels may display sizes differently, so this conversion is an approximation for web use.
Can negative pt values be converted to em?
Technically yes, negative pt values can be converted mathematically to em by the same formula, resulting in negative em values. However, negative font sizes don’t make sense in CSS and will be ignored or cause errors.
What happens if I change the browser’s default font size after converting 20 pt to em?
If the base font size changes, the meaning of em changes. For example, if default font size goes from 16 px to 20 px, then 1 em equals 20 px, so the em value corresponding to 20 pt will change accordingly, causing sizes to appear larger or smaller.