rem to px Converter & Guide
Convert rem values to pixels instantly. Useful for debugging computed styles, matching design specs, or understanding what rem values resolve to. Set your base font size and convert single values or entire CSS files. All client-side — no data leaves your browser.
CSS Unit Converter
Convert between px, rem, em, pt, vw, vh, and % with configurable base sizes.
1rem
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px ↔ rem Reference Table
Base font size: 16px
| px | rem | em | pt |
|---|---|---|---|
| 4px | 0.25rem | 0.25em | 3pt |
| 8px | 0.5rem | 0.5em | 6pt |
| 10px | 0.625rem | 0.625em | 7.5pt |
| 12px | 0.75rem | 0.75em | 9pt |
| 14px | 0.875rem | 0.875em | 10.5pt |
| 16px | 1rem | 1em | 12pt |
| 18px | 1.125rem | 1.125em | 13.5pt |
| 20px | 1.25rem | 1.25em | 15pt |
| 24px | 1.5rem | 1.5em | 18pt |
| 28px | 1.75rem | 1.75em | 21pt |
| 32px | 2rem | 2em | 24pt |
| 36px | 2.25rem | 2.25em | 27pt |
| 40px | 2.5rem | 2.5em | 30pt |
| 48px | 3rem | 3em | 36pt |
| 56px | 3.5rem | 3.5em | 42pt |
| 64px | 4rem | 4em | 48pt |
| 72px | 4.5rem | 4.5em | 54pt |
| 80px | 5rem | 5em | 60pt |
| 96px | 6rem | 6em | 72pt |
| 128px | 8rem | 8em | 96pt |
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How to convert rem to px
The formula is: px = rem × root-font-size. With the default root font size of 16px, 1rem = 16px, 1.5rem = 24px, 0.875rem = 14px, and 2.5rem = 40px. You can check the computed root font size in DevTools by inspecting the <html> element and looking at the computed font-size property. If your project uses html { font-size: 62.5% }, multiply rem by 10 instead of 16.
When you need rem to px conversion
You need rem-to-px conversion when: (1) comparing CSS values against pixel-based design specs from Figma, Sketch, or Adobe XD; (2) debugging why an element appears a different size than expected; (3) calculating exact pixel dimensions for images, SVGs, or canvas elements that need precise sizing; (4) setting border-width, outline, or box-shadow where sub-pixel rendering matters. Browser DevTools shows computed values in px, so knowing the conversion helps you map between your CSS source (rem) and rendered output (px).
Common rem to px values
At 16px base: 0.25rem = 4px, 0.5rem = 8px, 0.75rem = 12px, 1rem = 16px, 1.25rem = 20px, 1.5rem = 24px, 2rem = 32px, 2.5rem = 40px, 3rem = 48px, 4rem = 64px. Tailwind CSS spacing scale maps to these values: space-1 (0.25rem/4px), space-2 (0.5rem/8px), space-4 (1rem/16px), space-8 (2rem/32px). The reference table below updates dynamically when you change the base font size.
Frequently Asked Questions
How many pixels is 1rem?
1rem equals 16 pixels by default (the browser's default root font size). If your CSS changes the root font size with html { font-size: ... }, 1rem equals that value instead. For example, html { font-size: 20px } makes 1rem = 20px.
How do I find the root font size in my browser?
Open DevTools (F12), select the <html> element in the Elements panel, and check the Computed tab for font-size. This shows the actual root font size in pixels, which is the base for all rem calculations. Most browsers default to 16px unless overridden by CSS or user settings.
Does rem to px conversion change with browser zoom?
Browser zoom scales both rem and px proportionally, so the ratio stays the same. If 1rem = 16px at 100% zoom, it's still 1rem = 16px at 200% zoom — both values double together. The rem-to-px conversion formula doesn't change with zoom level.
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