Free Online REM to PX Visualizer
Convert rem values to pixels and preview different root sizes.
Separate values with commas, spaces, or new lines. Up to 40 values are converted at once.
| REM | Pixels | Preview |
|---|
Live preview
REM is relative to the root element. If a user changes their browser font size, the pixel result changes with it, which is why rem-based layouts respect accessibility settings better than fixed pixels.
About the REM to PX Converter
REM and pixels describe the same thing from different angles. A pixel is an absolute unit in CSS, while a rem is a multiple of the root font size. On a default browser that root is usually 16px, so 1rem equals 16px, 1.5rem equals 24px, and 0.875rem equals 14px. Change the root to 18px and every rem value grows with it while the pixel values change accordingly. This converter shows both directions at once, with a live type preview so the numbers stay connected to something visible.
Converting in both directions
In REM to PX mode, each value is multiplied by the root font size. In PX to REM mode, each pixel value is divided by the root. You can paste a comma-separated list, space-separated values, or one value per line; the converter extracts the numbers and ignores labels and punctuation. The table always shows both columns, which makes it easy to check a design handoff that mixes the two units. The preview renders a sample at each converted pixel size, capped visually so very large values do not break the layout.
Why rem is usually the better choice
Browsers let users set a preferred default font size, and rem units honor that preference. A layout built entirely in pixels ignores it, so text can stay uncomfortably small for someone who needs larger type. Rem also keeps a systematic relationship between components: if the root changes, padding, type, and spacing scale together. Pixels still make sense for hairline borders, shadows, and cases where a design must not move at all. A practical pattern is rem for type and spacing, pixels for fine visual details.
Common pitfalls
The root font size is not always 16px. A CSS reset, a framework, or a user preference can change it, so confirm
the computed value before converting a large stylesheet. Nested elements using em compound, while
rem always refers to the root and does not compound. Media queries written in rem also use the root size in some
browsers, which can shift breakpoints if the root changes. The converter assumes a single root value for all
rows, which is exactly what rem does.
Frequently asked questions
Is 1rem always 16px?
No. Sixteen pixels is only the common browser default. Users can change it, and CSS can override it with a rule on the html element. Always convert against the actual root size in the project you are working on.
What is the difference between rem and em?
Rem is relative to the root font size. Em is relative to the font size of the element itself, so nested em values multiply. That makes em useful for components that should scale with their own text, but harder to predict across deep nesting.
Can I convert negative values?
The converter focuses on sizes and spacing, so it ignores negative numbers. Negative margins and offsets are possible in CSS, but they are rarely expressed as font sizes and are better handled directly in the stylesheet.