Mario Kart is one of the best-selling franchises, selling over 111 million units despite there only being 8 entries so far.
Sales below use the latest numbers from Nintendo shipments found here  and associated pages
|1992||SNES||Super Mario Kart||8.76|
|1997||Nintendo 64||Mario Kart 64||9.87|
|2001||Game Boy Advance||Mario Kart: Super Circuit||5.91|
|2003||GameCube||Mario Kart: Double Dash!||6.88|
|2005||DS||Mario Kart DS||23.60|
|2008||Wii||Mario Kart Wii||36.75|
|2011||3DS||Mario Kart 7||13.94|
|2014||Wii U||Mario Kart 8||8.00|
|Franchise total (as of December 31, 2015)||113.71|
Mario Kart WiiEdit
Mario Kart Wii had an incredibly successful launch and sold 300,000 copies on the launch day in Japan alone, compared to Mario Kart DS which sold 160,000 copies on its first day and Mario Kart: Double Dash!! which sold 180,000 on its first day. Only three days later it had sold a total of over half a million copies in Japan. In the week ending May 4, 2008, Mario Kart Wii had sold over a million copies in Japan, less than a month since its release in the region. In the UK, Mario Kart Wii was the best-selling video game in the week ending April 12, 2008, having "the eighth biggest opening sales week in UK software history," according to ChartTrack/ELSPA. In France, the game has sold 453K copies as of June 2008. The game dwarfed all other five Mario Wii games combined (Mario & Sonic at the Olympics, Super Mario Galaxy, Super Paper Mario, Mario Party 8, and Mario Strikers Charged) when comparing first week sales. In North America, Mario Kart Wii sold 1.12 million copies in its first four days of release (from April 27-30), according to the NPD Group. This puts Mario Kart Wii at #2 of the best selling video games of April in North America, behind the Xbox 360 version of Grand Theft Auto IV and ahead of the PlayStation 3 version, both released in the same week. As of September 2015, 36.53 million copies have been sold worldwide.
Mario Kart 7Edit
Mario Kart 8 Edit
The game launched with great sales, with 1.2 million in sales in the first 4 days on the market with 325,892 sold retail in Japan according to Media Create. It increased sales of the Wii U by 666% compared to the week before with its release. By June 30, 2014, it sold 2.88 million. By end of July, it sold over 1 million copies in America. By October 2014, the game has sold 3.49 million. by January, the game sold 4.77 million total.
In Japan, the game sold over 840,000 copies by the end of 2014. In France, the sales number was 346,000. In the US, the game has sold over 1.7 million.
Currently, it is at 8.0 million, which is an amazing attach rate with over half of Wii U owners owning it despite it lacking bundles until months later.