
It's about as big as a Postage Stamp.
(average; United States dimensions)
A typical postage stamp measures an average of 0.60 square inches. One of the most prized stamps among collectors is the USissued "Inverted Jenny" stamp printed in 1918, which features an upsidedown image of Curtiss JN4 ("Jenny") airplane; a single stamp sold for $977,500 at a 2007 auction.
It's about as big as a Quarter.
(United States quarterdollar coin) (a.k.a. Quarter dollar, a.k.a. Washington quarter, a.k.a. two bits)
The George Washington quarter, in circulation in various forms since 1932, has a diameter of 24.26 mm (0.955 in) and an area of 0.71640 square inches.
It's about oneandthreetenths times as big as a Nickel.
In other words, 0.71640 square inches is 1.3080 times the size of a Nickel, and the size of a Nickel is 0.76450 times that amount.
(United States fivecent coin) (a.k.a. Jefferson nickel)The nickel, in its current design since 1938, has a diameter of 21.21 mm (0.835 in) and an area of 0.54760 square inches.
It's about oneandthreefifths times as big as a Penny.
In other words, 0.71640 square inches is 1.620 times the size of a Penny, and the size of a Penny is 0.6170 times that amount.
(United States onecent coin) (a.k.a. Lincoln penny, a.k.a. Cent, a.k.a. One cent piece)The Lincoln penny, in its current design since 1909, has a diameter of 19.05 mm (0.75 in) and an area of 0.4420 square inches.
It's about threefifths as big as a Secure Digital (SD) card.
In other words, the size of a Secure Digital (SD) card is 1.70 times 0.71640 square inches.
A Secure Digital (SD) card measures 3.2 cm by 2.4 cm for a total area of 1.20 square inches. SDXC Cards, the latest standard for the technology, will allow the cards to hold up to 2 terabytes of data.
It's about oneandfourfifths times as big as a Dime.
In other words, 0.71640 square inches is 1.8350 times the size of a Dime, and the size of a Dime is 0.5450 times that amount.
(United States tencent coin) (a.k.a. Roosevelt dime)The dime, in its current design since 1946, has a diameter of 17.91 mm (0.705 in) and an area of 0.39040 square inches.
It's about six times as big as a Nailhead.
In other words, 0.71640 square inches is 5.9450 times the size of a Nailhead, and the size of a Nailhead is 0.16820 times that amount.
(for 11gauge wire nai)An 11gauge nailhead measures 0.12050 square inches. Nails have been used since ancient times; archaeologists have discovered Ancient Egyptian nails that are over 5,000 years old. 
