MM to EM Converter
Use this free online mm to em converter tool to convert millimeters to em units. Millimeters are a precise metric unit while EM is a scalable web unit based on parent font-size. Essential for converting precise metric measurements to web design.
To convert millimeters to em, first convert to pixels (mm × 96 ÷ 25.4), then divide by the parent font-size. The default parent font-size is 16px. This bridges precise metric measurements with parent-relative web units.
Conversion Formula
em = (mm × 96 ÷ 25.4) ÷ parent font-size
For example, to convert 25.4mm (1 inch) to em with 16px parent font-size, calculate (25.4 × 96 ÷ 25.4) ÷ 16 = 6em. Similarly, 12.7mm equals 3em.
MM to EM Converter Conversion Table (Parent: 16px)
| MM | EM |
|---|---|
| 1mm | 0.2362em |
| 2mm | 0.4724em |
| 5mm | 1.181em |
| 10mm | 2.362em |
| 15mm | 3.543em |
| 20mm | 4.724em |
| 25.4mm | 6em |
| 30mm | 7.087em |
| 40mm | 9.449em |
| 50mm | 11.81em |
| 75mm | 17.72em |
| 100mm | 23.62em |
| 127mm | 30em |
| 150mm | 35.43em |
| 200mm | 47.24em |
| 254mm | 60em |
What is MM?
Millimeters (mm) are an absolute CSS unit representing physical millimeters, primarily used for precise print measurements. In web contexts, 1mm equals approximately 3.78 pixels. Millimeters are most useful in print stylesheets and international design contexts where metric precision is required.
What is EM?
EM is a relative CSS unit that scales based on the parent element's font size, making it highly context-dependent. By default, 1em equals the parent element's font-size value, creating a cascading effect through nested elements. While EM offers flexibility for component-level scaling, its cascading nature can make it unpredictable compared to REM in complex layouts.