How to turn hexadecimal into decimal using brain

hex

Opening the calculator to do such tiny stuff appears annoying to me ,and I strongly believe in ths saying "the more you know,the better!" so here I am asking you how to convert hexadecimal to decimal.

Till that moment I use the following formula:

Hex:        Decimal:
12          12+6
22          22+2*6
34          34+3*6
49          49+4*6
99          99+9*6

I get confused when I move on at higher numbers like C0 or FB

What is the formula(brain,not functional) that you're using?

Best Solution

If you consider that hexadecimal is base 16, its actually quite easy:

Start from the least significant digit and work towards the most significant (right to left) and multiply the digit with increasing powers of 16, then sum the result.

For example:

0x12 = 2 + (1 * 16) = 18

0x99 = 9 + (9 * 16) = 153

Then, remember that A = 10, B = 11, C = 12, D = 13, E = 14 and F = 15

So,

0xFB = 11 + (15 * 16) = 251

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