A In Decimal

a in decimal is 10. Full conversion of a (hexadecimal) to binary 1010, decimal 10 and hex A.

How this conversion works

Hex borrows letters once it runs out of digits, so A is simply 10. B through F carry on to 15, after which the next place value (16) begins.

Each base just uses a different set of digits for the same quantity. Reading a as a hexadecimal number gives the decimal value 10; expressing that same value in base two, eight or sixteen produces the rows above. To convert any number between bases — including custom bases from 2 to 36 — use the number base converter.