The gas tank on the 2013 Mazda MAZDA6 holds 18.5 gal..
The gas tank on the 2004 Mazda MAZDA6 holds 18 gal..
The gas tank on the 2012 Mazda MAZDA6 holds 18.5 gal..
The gas tank on the 2006 Mazda MAZDA6 holds 18.0 gal..
The gas tank on the 2009 Mazda MAZDA6 holds 18.5 gal..
The gas tank on the 2015 Mazda MAZDA6 holds 16.4 gal..
The gas tank on the 2008 Mazda MAZDA6 holds 18.0 gal..
The gas tank on the 2007 Mazda MAZDA6 holds 18.0 gal..
The gas tank on the 2011 Mazda MAZDA6 holds 18.5 gal..
The gas tank on the 2005 Mazda MAZDA6 holds 18.0 gal..
The gas tank on the 2003 Mazda MX-5-Miata holds 12.7 gal..
AnswerMine holds anywhere from 13-15 gallons.----------------------------i have a 2003 mazda6 and it holds 18 gallons and says it in the owner's manual.