Px to Rem Converter

What Are 0.9rem, 1.4rem, and Other Rem Values in Pixels?

0.9rem is 14.4px at a 16px base. The formula is px = rem × root font size in pixels; reverse it with rem = px ÷ root font size. These examples use the converter's initial 16px base, so change that field if your page uses a different computed root size.

Rem	Pixels at a 16px base
0.25rem	4px
0.9rem	14.4px
1.125rem	18px
1.2rem	19.2px
1.4rem	22.4px
1.5rem	24px

Select rem → px / em and enter the rem value to reproduce a row. The displayed results round to at most four decimal places. The copyable CSS shows the converted value with the original value in a comment, making it easier to compare the output with your source stylesheet.

Why Convert Pixels to Rem in CSS?

A CSS pixel is a device-independent length unit. A rem is a multiple of the root element's computed font size. When that root size is 16px, 1rem equals 16px, 1.5rem equals 24px, and 2rem equals 32px. Converting a design measurement to rem expresses it relative to that root rather than keeping it as a fixed CSS pixel value.

This can help typography and spacing respond together when the root font size changes. For example, a 1.5rem heading becomes 30px when the root grows from 16px to 20px. A 24px heading keeps its CSS pixel size under that root change, although browser zoom can still enlarge it. Unit choice alone does not guarantee accessible text resizing: test the complete layout for clipping, overlapping controls, and lost content as text grows.

The converter performs arithmetic only. It does not read styles from your website, detect inherited font sizes, inspect media queries, or certify accessibility. Find the actual computed root font size in your browser's style inspector and enter it as the base. Using an assumed base that differs from your page can produce a mathematically correct conversion that is wrong for the layout you are editing.

How Does Rem Conversion Work Mathematically?

For pixels to rem, divide by the base: 24px ÷ 16px = 1.5rem. For rem to pixels, multiply by the base: 1.5 × 16px = 24px. The base field accepts a positive number. If it is empty, invalid, or nonpositive, the converter shows an error and suspends calculations. A decimal base is also usable when that matches the computed root font size.

The tool calculates rem from the root font size and em from the separate parent font size. In real CSS, em depends on its context. For an element's font-size, it refers to the parent font size; for many other lengths, it refers to the element's own font size. A child with font-size: 0.9em under a 20px parent computes to 18px, while 0.9rem at a 16px root is 14.4px. Enter the relevant context yourself when using the em output.

What Are Common Pixel-to-Rem Conversion Values?

The formula for this reference is rem = pixel value ÷ 16. The interactive quick reference uses your selected base instead, so its values update when that base changes. These examples can help compare spacing and font-size values without assuming a particular heading scale or visual design.

Pixels	Rem at a 16px base
8px	0.5rem
12px	0.75rem
14px	0.875rem
16px	1rem
18px	1.125rem
20px	1.25rem
24px	1.5rem
32px	2rem
48px	3rem
64px	4rem

How Do I Use Fluid Typography with Rem and clamp()?

CSS clamp() bounds a preferred value between a minimum and maximum. For example, font-size: clamp(1rem, 2.5vw, 1.5rem) has a 16px minimum and 24px maximum when the root is 16px. Its preferred value uses viewport width. The converter can calculate those rem boundaries, but it does not evaluate the viewport-dependent expression or generate a fluid type scale.

Relative boundaries do not by themselves guarantee accessible resizing. Check the page at enlarged text settings and different viewport widths. A heading can reach its maximum while the preferred viewport value still responds differently from user font preferences. Use the arithmetic here to understand individual values, then verify their behavior in the real stylesheet. The batch converter is useful for converting several fixed boundary values with the same root size.

What Is the 10px Rem Trick and Should I Use It?

Setting html { font-size: 62.5%; } makes the root 10px when the inherited browser default is 16px: 16 × 0.625 = 10. That percentage still responds to a changed default; with a 20px default, the root becomes 12.5px. It does not inherently disable user preferences. Enter the actual computed root size rather than assuming this declaration always means 10px.

At a 10px root, 14px converts to 1.4rem and 24px to 2.4rem. At a 16px root, those same pixel values convert to 0.875rem and 1.5rem. Choose the base that matches the stylesheet you maintain. The tool supports either convention and does not modify the root element or rewrite CSS files. Paste a list of numeric values into Batch Converter to obtain separate declarations you can review before copying.