What Size Is A3?
The size of an A3 paper is 297 x 420 millimeters or 11.69 x 16.54 inches. 
This paper size is used for spreads, tables, drawings, diagrams and various office and school projects.
The ISO Paper Standards
The A3 paper is part of the ISO paper standards called the A series. The biggest of the A series is A0 and the smallest is A10. The A3 size is comparable to the tabloid paper size used in the United States. The tabloid size is 11 x 17 inches.
Another popular size is the A4, which measures 8.27 inches by 11.69 inches. This is comparable to the 8.5 x 11 letter size. The A5 paper is another widely used paper. It measures 5.83 inches by 8.27 inches. In terms of size comparison, it is in the middle of 8.5 inch by 5.5 inch “Statement” size and the US 8 x 5 index card.
Usage
The size of an A3 paper has made it the standard in most nations around the world. Aside from the ones mentioned earlier, it is also used wisely in photo papers. One of the reasons for its popularity is the way it handles camera sensor ratios.
Even though the A3 is not a standard in the US, almost all printers sold have support for the ISO sizes. You can change the paper size in the page layout tab of the program. In other applications, you may have to click the “page layout” or “page setup” menu. You must also change the options at the printer dialog box.
Where to Buy
The A3, A4 and other ISO paper sizes can be purchased in office supply stores. These papers are also available in numerous finishes. Plain paper is the most widely used. But there are also matte, glossy and photo paper types available.
Aside from stores, these papers can also be purchased online. One of the nice things about buying online is you can check their properties and compare the prices. A3 paper sizes are not that expensive.
But if you are going to buy a lot, the cost may go up. Fortunately, some sites will offer discounts if you buy the paper in bulk. Check different sites so you can compare the prices.
These days you will not have any problems working with the size of an A3 paper. Because of the way printers are set up, one can now use this paper size with ease.
