12 inches Ruler — Actual Size
Use this ruler to visualize and measure exactly 12 inches on your screen. After calibrating with a credit card or reference object, the ruler above displays 12 in at its true physical size on any device — phone, tablet, or desktop. For reference, 12 in is close to the size of a standard 30cm ruler.
Unit Conversions for 12 inches
30.48
centimeters
304.8
millimeters
12.00
inches
How to Measure 12 inches
- Open this page on the device you want to measure with and use the ruler displayed above.
- Calibrate by placing a credit card on the screen and adjusting the slider until the outline matches the card. This takes about 10 seconds.
- Place the object you want to measure against the ruler. The markings show centimeters, millimeters, and inches, so you can read 12 in directly.
- Your calibration is saved in the browser, so the ruler remains accurate on your next visit.
About This Measurement
12 inches equals 304.8 millimeters or 12.00 inches. One inch equals exactly 25.4 millimeters or 2.54 centimeters. Inches are part of the imperial system used primarily in the United States, United Kingdom, and Canada.
A real-world object close to 12 in in size is a standard 30cm ruler. You can use such objects to get a quick sense of scale without a ruler.