Conversion Form

PERCENTAGE
MM

About the Unit

Percentage (%): Percentage is a relative unit of measurement that expresses a value as a fraction of 100. It is widely used in CSS to define dimensions of elements in a fluid and adaptable manner. For example, if you define an element's width as 50%, it will occupy half of its parent element's width. Using percentages allows elements to automatically adjust based on their container’s size, which is ideal for creating responsive layouts that work well on different devices, such as smartphones, tablets, and desktops. Percentage is also useful for properties like margin, padding, and height, where you want the element to adjust proportionally to its parent container, rather than setting a fixed value. This unit is essential for creating flexible and adaptable layouts where content adjusts automatically to changes in screen size or device layout.

Pro Tip: percentage → mm

For small precise measurements, use mm, for fluid layouts use %.

Quick Reference: Unit Conversion by Tens

PERCENTAGEMM
10%2.645833mm
20%5.291667mm
30%7.9375mm
40%10.583333mm
50%13.229167mm
60%15.875mm
70%18.520833mm
80%21.166667mm
90%23.8125mm
100%26.458333mm
110%29.104167mm
120%31.75mm
130%34.395833mm
140%37.041667mm
150%39.6875mm
160%42.333333mm
170%44.979167mm
180%47.625mm
190%50.270833mm
200%52.916667mm
210%55.5625mm
220%58.208333mm
230%60.854167mm
240%63.5mm
250%66.145833mm

Live Unit Preview

See how different CSS units affect the size of the box below:

10px

10rem

10em

10%

10vw

10vh

Common Mistake

For small precise measurements, use mm, for fluid layouts use %.

Real Code Example

/* Mobile-first card with percentage → mm */
.card {
  padding: 0%;     /* undefinedmm */
  font-size: 1.5rem;
  width: min(90vw, 40ch);
}

Frequently Asked Questions About PERCENTAGE

When should I use percentage instead of percentage?

Use percentage for fluid layouts and relative sizing.

How many percentage is 100percentage?

100% equals the full size of the parent.

Is percentage affected by parent size?

Yes, it's entirely dependent on the parent.

Is percentage good for widths?

Yes, it's ideal for responsive widths.

Keyboard Shortcuts

  • Ctrl + C: Convert
  • Ctrl + I: Invert units
  • Esc: Reset values

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