1 px equals 0.0625 rem.
This conversion assumes the root font size is 16 pixels, which is the usual default in most browsers. To convert pixels to rem units, divide the pixel value by the root font size. So, 1 pixel divided by 16 equals 0.0625 rem, making rem a scalable unit based on the root font size.
Conversion Tool
Result in rem:
Conversion Formula
The formula to convert pixels (px) to rem units is:
rem = px ÷ root font size
Where the root font size is commonly 16px, but it can be different depending on CSS settings or browser defaults. The rem unit stands for “root em” and relates to the root element’s font size, making it scalable.
For example, to convert 1px to rem:
- Identify root font size (default is 16px).
- Divide 1px by 16px.
- 1 ÷ 16 = 0.0625 rem.
This formula works because rem is relative to the root font size, not to the element’s parent, so it keeps sizing consistent across the page.
Conversion Example
- Example: 8px to rem
- Divide 8 by 16 (root font size).
- 8 ÷ 16 = 0.5 rem.
- So, 8px equals 0.5 rem.
- Example: 24px to rem
- Divide 24 by 16.
- 24 ÷ 16 = 1.5 rem.
- 24px converts to 1.5 rem.
- Example: 12px to rem
- 12 ÷ 16 = 0.75 rem.
- Therefore, 12px is 0.75 rem.
- Example: 20px to rem
- 20 ÷ 16 = 1.25 rem.
- Hence, 20 pixels is 1.25 rem units.
- Example: 5px to rem
- 5 ÷ 16 = 0.3125 rem.
- So, 5px equals 0.3125 rem.
Conversion Chart
| Pixels (px) | Rem |
|---|---|
| -24.0 | -1.5000 |
| -20.0 | -1.2500 |
| -16.0 | -1.0000 |
| -12.0 | -0.7500 |
| -8.0 | -0.5000 |
| -4.0 | -0.2500 |
| 0.0 | 0.0000 |
| 4.0 | 0.2500 |
| 8.0 | 0.5000 |
| 12.0 | 0.7500 |
| 16.0 | 1.0000 |
| 20.0 | 1.2500 |
| 24.0 | 1.5000 |
| 26.0 | 1.6250 |
Use this chart by finding the pixel value in the left column, then look right to see the equivalent rem value based on 16px root font size. Negative values can represent offsets or margins in CSS, while positive values are common for font sizes and spacing.
Related Conversion Questions
- How many rem units equal 1 pixel with a 16px root font size?
- What is the rem value of 1px if the browser root size changes?
- Can 1px be converted to rem when root font size is not 16px?
- Why does 1px convert to 0.0625 rem in CSS?
- How does changing root font size affect 1px to rem conversion?
- Is 1px always the same in rem across different browsers?
- How to calculate rem from px for 1 pixel precisely?
Conversion Definitions
px (pixel): A pixel is the smallest unit of measurement in digital displays, representing a single point in a raster image or on a screen. Pixels are fixed in size relative to the display’s resolution, making them absolute units for defining element dimensions in CSS, images, and screen content.
rem (root em): Rem is a relative length unit in CSS that scales according to the font size of the root element (<html>). Unlike em units, rem always references the root font size, which allows consistent scaling of elements regardless of nesting, useful for responsive design and accessibility.
Conversion FAQs
Does the root font size affect how 1px converts to rem?
Yes, the root font size is the divisor in the conversion formula. If the root font size changes from the default 16px to something else, the rem value for 1px changes accordingly. For example, if root font size is 20px, 1px would equal 0.05 rem instead of 0.0625 rem.
Can I rely on 1px being a fixed size in rem across devices?
No, since rem is relative to the root font size, which might vary between browsers or user settings, 1px converted to rem can differ in visual size. Pixels are fixed units, but rem scales, so the exact size depends on root font size and user preferences.
Why convert px to rem instead of using px directly?
Using rem units allows for scalable layouts that respond to user font size settings and improves accessibility. Pixels are absolute and don’t scale, making rem units better for flexible design. Converting 1px to rem helps keep small sizes consistent relative to the overall page scaling.
How precise is the conversion from 1px to rem?
When using 16px as the root font size, 1px equals exactly 0.0625 rem. This is a precise mathematical conversion. However, rounding in CSS or browser rendering might make tiny differences, but generally it is accurate enough for layout calculations.
Are negative pixel values meaningful when converting to rem?
Negative pixel values can represent offsets or negative margins in CSS. Converting these to rem works the same way by dividing by the root font size, resulting in negative rem values that maintain the relative proportions and effects in layouts.