There are 100 millimeters in 10 centimeters. This is because 1 centimeter is equal to 10 millimeters. To find out how many millimeters are in 10 centimeters, you simply multiply 10 centimeters by 10 millimeters per centimeter. So, 10 cm × 10 mm/cm = 100 mm. This conversion is straightforward and is based on the metric system, which is widely used around the world for its simplicity and consistency.