Pixel	Rem
1 px	0.0625 rem
2 px	0.125 rem
3 px	0.1875 rem
4 px	0.25 rem
5 px	0.3125 rem
6 px	0.375 rem
8 px	0.5 rem
10 px	0.625 rem
12 px	0.75 rem
14 px	0.875 rem
15 px	0.9375 rem
16 px	1 rem
18 px	1.125 rem
20 px	1.25 rem
24 px	1.5 rem
25 px	1.5625 rem
28 px	1.75 rem
32 px	2 rem
36 px	2.25 rem
40 px	2.5 rem
44 px	2.75 rem
48 px	3 rem
50 px	3.125 rem
56 px	3.5 rem
64 px	4 rem
72 px	4.5 rem
75 px	4.6875 rem
80 px	5 rem
90 px	5.625 rem

Rem	Pixel
1 rem	16 px
2 rem	32 px
3 rem	48 px
4 rem	64 px
5 rem	80 px
6 rem	96 px
8 rem	128 px
10 rem	160 px
12 rem	192 px
14 rem	224 px
15 rem	240 px
16 rem	256 px
18 rem	288 px
20 rem	320 px
24 rem	384 px
25 rem	400 px
28 rem	448 px
32 rem	512 px
36 rem	576 px
40 rem	640 px
44 rem	704 px
48 rem	768 px
50 rem	800 px
56 rem	896 px
64 rem	1024 px
72 rem	1152 px
75 rem	1200 px
80 rem	1280 px
90 rem	1440 px

PX and REM

In web development, PX (Pixel) and REM (Root Em) are units used to specify spacing, font sizes, and other length measurements in CSS. Here is a brief explanation of both units:

PX (Pixel)

Definition: A pixel is the smallest unit of a digital image or display.
Usage: Specifying in pixels (px) is absolute, meaning the size is fixed and independent of other factors.
Example: font-size: 16px; sets the font size to 16 pixels.
Advantages: Easy to use and predictable, as they have a fixed size.
Disadvantages: Can appear differently on various devices and screen resolutions and is less flexible when adapting to different screen sizes.

REM (Root Em)

Definition: A REM unit is based on the font size of the root element (<html>).
Usage: Specifying in REM is relative to the font size of the root element, meaning changes to the root element's font size affect the size of all elements specified in REM.
Example: If the font size of the root element (<html>) is 16px, then 1rem equals 16px. font-size: 2rem; would be 32px in this case.
Advantages: Allows for consistent and flexible design, as changes to the root element's size automatically apply to all values specified in REM.
Disadvantages: Can be initially more complex to understand and use, especially when many nested elements are involved.

Comparison and Recommendation

Responsive Design: REM units are often better suited for responsive design as they can be easily scaled by adjusting the root font size.
Consistency: REM can lead to a more consistent user experience, especially on different screen sizes and resolutions.

Example

Here is a simple example to illustrate the difference:

html {
    font-size: 16px; /* Sets the base font size */
}

body {
    font-size: 1rem; /* 1rem equals 16px */
}

h1 {
    font-size: 2rem; /* 2rem equals 32px */
}

p {
    font-size: 16px; /* Fixed font size of 16px */
}

REM to PX converter

Conversion tables

PX and REM

PX (Pixel)

REM (Root Em)

Comparison and Recommendation

Example