Which car is cheaper to drive, accounting for mpg and gas prices?

Ok so my ford excursion is diesel and gets 14.5 mpg and diesel prices cost around $2.91. While my Honda Odyssey is gas and gets 21 mpg and gas prices are around $3.24. If it matters the excursion has a 44 gallon tank and the oddysey has a 20 gallon tank.

The Ford is costing you 20.07 per mile.
The Honda is costing you 15.43 per mile.

Tank size is irrelevant.

Cost per mile:
$2.91/14.5=$.20
$3.24/21=$.154
Size if tank is totally irrelevant!

The dodge costs about 5 cents per mile to drive, the honda runs aorund 6.5 cents.so they are pretty close but the honda is slightly cheaper.