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Lettergrootteconverter (pt, px, rem, em, %)

Converteer lettergroottes tussen pt, px, rem, em en percentages voor web en print, met instelbare browserbasisgrootte.

Value

Source unit

Browser base size (px) Default browser is 16px. Many designs use 10px ("62.5%") for easy math.

Parent em size (px) em is relative to its parent; rem is relative to the root.

Converted size

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Preview:

The quick brown fox jumps over the lazy dog.

Unit	Value	CSS

Hoe de berekening werkt

1 pt = 1.3333 px at 96 DPI (CSS standard). 1 rem = base px. 1 em = parent px. 100% = parent px. All conversions route through pixels first.

Use rem for accessible body text (respects user zoom), em for component-scoped sizing, px for fixed UI chrome.

Hoe de berekening werkt

Every unit routes through pixels first. Points use the CSS reference of 96 DPI, so 1 pt = 1.3333 px; rem multiplies by Browser base size (px); em and % both multiply by Parent em size (px), with the percentage divided by 100 beforehand. The resulting pixel value is then pushed back out to all five units simultaneously and applied to the live preview line, so you can see the size rather than only read it.

The two base fields do different jobs, and they are why answers differ. Browser base size (px) is the root font size — 16 by default, or 10 if you use the 62.5% trick — and only rem depends on it. Parent em size (px) is the computed size of the containing element, and it drives both em and %. Set them independently; leaving both at 16 makes rem and em look interchangeable when they are not.

The conversion is exact but the context around it is not. Real em values compound down a nesting chain, so 0.9em inside 0.9em resolves to 0.81, and this tool models only a single level — deeply nested components will not match. Points are treated as the CSS reference unit rather than a physical typographic point, so print measurements at other resolutions differ. Browser minimum font-size settings and text-size-adjust are ignored entirely.

Veelgestelde vragen

How many pixels is 12pt?

16 px. CSS fixes 1 pt at one seventy-second of an inch and 1 px at one ninety-sixth, so the ratio is 96 ÷ 72 = 1.3333 regardless of your actual screen. That is why 12pt and 16px are both the default browser body size.

Should body text use rem or em?

Rem. It resolves against the root font size, so a reader who raises their browser's default text size scales your whole page with it. Em compounds at every nesting level, which is useful inside a component but unpredictable for base copy.

What is the 62.5% font-size trick?

Setting the root to 62.5% of the 16px default makes 1rem equal exactly 10px, so 1.8rem is 18px and the mental arithmetic disappears. Enter 10 in Browser base size (px) to convert against that setup instead of the standard 16px.

Why do em and % give me the same value?

Because for font-size both resolve against the parent element, and a percentage is simply em multiplied by 100. The tool uses the Parent em size (px) field for both. They only diverge in other properties, where the reference length is different.

Does 1rem always equal 16px?

Only when the root font size is 16px. That is the browser default, but users can change it in their settings, and any font-size declared on the html element overrides it. Set Browser base size (px) to match whatever your stylesheet actually declares.

Ook bekend als

font size converterpt to pxrem to px converterem to px

Lettergrootteconverter (pt, px, rem, em, %)

Hoe de berekening werkt

Veelgestelde vragen

Ook bekend als

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