I've created a spreadsheet for my boxes which I'm packing for my move, and I'm wondering if my math is correct.

What I've done is to measure each box in inches and divide each inch measurement by 12.

So if a box is 10 inches*12 inches*16 inches that would be 0.833 feet*1 feet*1.333 feet

Then I multipled those numbers together to come up with the cubic feet for that particular box: 1.11111 cubic feet.

And then I added all those cubic feet numbers together to come up with the total cubic feet. So let's say 30 boxes of that size would be 33.33 cubic feet.

Is that right?