To convert 11 inch to millimeter, multiply by the conversion factor 25.400000. So, 11 × 25.400000 = 279.4000 millimeter.

11 inch equals exactly 279.400000 millimeter. For practical purposes, this is often rounded to 279.4000 millimeter.

Objects measuring approximately 11 inch include the length of a US Letter size paper (11 inch, 279.4 mm), the screen diagonal of an Apple iPad Air (5th Gen) (10.9 inch, 276.86 mm), and a standard 11 inch adjustable wrench (279.4 mm).

Converting inch to millimeter is useful for ensuring compatibility in international manufacturing and trade, adhering to metric standards in scientific and engineering fields, and for precise measurements in professional applications where metric units are standard.

A simple memory aid is to remember that 1 inch is 25.4 mm. For 11 inch, you can think of it as "10 inches plus 1 inch". So, 10 inches is 254 mm, and adding another 25.4 mm gives 279.4 mm. Visualizing an 11 inch object, like a piece of paper, and knowing it is roughly 28 cm can also help.