MM → EM Converter
Converting from MM to EM is common when switching from for ultra-precise graphic designs. to ideal when you need sizing relative to parent elements. in CSS projects.
Conversion Form
About the Unit
Millimeter (mm): The millimeter (mm) is a physical unit of measurement, 1/10th of a centimeter. Like cm, mm is commonly used in graphic design and printing, where precise physical measurements are needed. In CSS, mm is useful for defining width, height, and other dimensions of elements in layouts that will be printed or converted to other physical formats. Using mm is an effective way to ensure precise and consistent layout dimensions during the printing process. For digital designs, the mm unit may be less practical, as most web interfaces benefit more from relative units to ensure a more adaptive user experience. However, for technical documents or precision graphics, mm may be the best choice.
Pro Tip: mm → em
Use mm for print design precision and em for scalable text.
Quick Reference: Unit Conversion by Tens
| MM | EM |
|---|---|
| 10mm | 0.393701em |
| 20mm | 0.787402em |
| 30mm | 1.181102em |
| 40mm | 1.574803em |
| 50mm | 1.968504em |
| 60mm | 2.362205em |
| 70mm | 2.755906em |
| 80mm | 3.149606em |
| 90mm | 3.543307em |
| 100mm | 3.937008em |
| 110mm | 4.330709em |
| 120mm | 4.724409em |
| 130mm | 5.11811em |
| 140mm | 5.511811em |
| 150mm | 5.905512em |
| 160mm | 6.299213em |
| 170mm | 6.692913em |
| 180mm | 7.086614em |
| 190mm | 7.480315em |
| 200mm | 7.874016em |
| 210mm | 8.267717em |
| 220mm | 8.661417em |
| 230mm | 9.055118em |
| 240mm | 9.448819em |
| 250mm | 9.84252em |
Live Unit Preview
See how different CSS units affect the size of the box below:
10px
10rem
10em
10%
10vw
10vh
Common Mistake
Be cautious when mixing mm and em without testing on different screen sizes.
Real Code Example
/* Mobile-first card with mm → em */
.card {
padding: 0mm; /* undefinedem */
font-size: 1.5rem;
width: min(90vw, 40ch);
}Keyboard Shortcuts
- Ctrl + C: Convert
- Ctrl + I: Invert units
- Esc: Reset values