Volumetric Weight in Inches
Many sellers measure boxes and polybags in inches, but courier formulas are written in cm. This calculator opens in inches and converts for you: each inch is 2.54 cm, so L × B × H in inches ÷ 5000 in cm becomes L × B × H ÷ 305 in inches.
Example: a 12 × 10 × 8 inch box is 960 cubic inches. 960 ÷ 305 = 3.15 kg volumetric weight, charged as 3.5 kg. A 10 × 8 × 4 inch box is 320 ÷ 305 = 1.05 kg, charged as 1.5 kg — trimming one inch of height (10 × 8 × 3) brings it to 0.79 kg, charged as 1 kg.