Tank Chart Calculator HomeResourcesTank Chart Calculator Tank Chart Calculator This tank chart capacity program will allow you to calculate tank charts* for tanks with flat heads. All physical dimensions must be supplied in inches. Tank Orientation(Required) Horizontal Vertical Rectangle Output Increment(Required) 1/8 in. 1/4 in. 1/2 in. 1 in. Diameter (in inches)(Required)Length/Height (Verticals, in inches)(Required)Length (in inches)(Required)Width (in inches)(Required)Height (in inches)(Required)