Most oil heat dealers will have a chart that does just what you want, converting inches of oil in the tank to gallons. I found links to two dealers that have put the chart online. Looking at the charts side by side they don't match exactly but are close enough for most of us.
http://www.oilforless.com/tankchart.html
http://www.ableenergy.com/se/capacity.asp
=There are 1,605.12 gallons in 481,536 cubic inches.==There are 1,605.12 gallons in 481,536 cubic inches.=
To convert cubic inches to gallons, divide cubic inches by 231:Cubic inches / 231 = US gallons
10 gallons
3.69 gallons is 852.39 cubic inches.
Conversion: cubic inches x 0.003605 = Imperial gallons
Inches and gallons are like chalk and cheese - cannot be compared.
There are 25.71 gallons of water in 5,940 cubic inches.
Use this formula: cubic inches x 0.004329 = gallons
A tank of 21 inches wide, 8 inches deep and 59 inches long will hold 36 gallons of gas. These gallons refers to US gallons.
18.7013 US gallons.
38 cubic inches is about 0.16 US gallons.
No, they are not related. Gallons is a unit of volume and inches is unit of a length.