Instantly convert EM to MM and MM to EM
A simple and fast tool to convert EM units to millimeter (mm) values and vice versa for your web and print designs.
How to Convert EM to MM
Step 1: Determine the Parent’s Font Size
Identify the font-size of the direct parent element in pixels. The `em` unit is relative to this value. Enter it in the “Parent Font Size” field above.
Step 2: Use the Conversion Formula
The formula to convert EM to millimeters is: `(EM Value * Parent Font Size) * 25.4 / 96`. This is based on the standard of 96 pixels per inch, and 25.4 millimeters per inch.
Result in MM = (EM * Parent PX) * 25.4 / 96
Step 3: Example Calculation
If you want to convert 2em to millimeters and the parent’s font size is 24px, the calculation is:
(2 * 24) * 25.4 / 96 = 12.7
So, 2em is equal to 12.7mm in this context.
Common EM to MM Reference
A quick reference table based on the parent font size set above.
EM to MM Converter Information
Understanding EM Units
The `em` unit is a relative unit of measurement in CSS. It is relative to the font-size of its direct parent element. This makes it powerful for creating components that scale within themselves, but can sometimes lead to complex calculations in nested elements.
Understanding Millimeters (MM)
The millimeter (mm) is a standard metric unit of length, equal to one-thousandth of a meter. It is used worldwide for precise physical measurements. In digital design, converting to millimeters is essential for tasks that require a bridge between the screen and the physical world, based on a standard screen density (DPI).
Why Convert EM to MM?
Converting `em` to `mm` is useful when you need to align scalable web designs with fixed physical measurements for print or other real-world applications. This is important for:
- Print and Manufacturing: For any design that will be printed or physically produced, such as packaging, labels, or business cards, converting to millimeters is necessary for accurate sizing.
- Technical and Engineering Drawings: In fields like architecture and engineering, where precision is paramount, converting digital plans to millimeters ensures they meet real-world specifications.
- Crafting and Prototyping: Whether for 3D printing or other crafting hobbies, converting pixel-based designs to millimeters allows for the creation of accurately-sized physical prototypes.