2' 4 should be 80cm. If you wear pants of European size, it should be 3 1 size.

Try to popularize clothing size by the way

2' 4 is a city ruler, and the conversion from city ruler to cm should be 33.3333 cm, so it should be 2.4X3.33=79.92cm.

The European code is calculated in inches, and one inch is 2.54cm, so you use the waist circumference of 79.92÷2.54=3 1.49 inches.

So your pants should be 3 1 yard.