CVT is rated 28 mpg in town, 30 mpg highway, 29 combined (3.45 gallons per 100 miles). Manual: 24/29/26. Trip computer in preproduction CVT tester: 24.2 mpg in highway driving (4.13 gal./100 mi.) in stiff wind.
Uses regular; holds 13.2 gallons.
http://www.usatoday.com/money/autos/reviews/healey/2009-04-16-nissan-cube-usa_N.htm
