521 mm to Inches on a Ruler
521 millimeters is equal to 20.5 inches on a ruler.
The place marked in red shows 20.5 inches, which is equal to 521 millimeters on the ruler.
Try these similar conversions:
522 mm to inches on a ruler
Convert 522 millimeters to inches and see it on a ruler.
520 mm to inches on a ruler
Convert 520 millimeters to inches and see it on a ruler.