Here’s an assortment of code to convert between different base systems. I have provided code in both Visual Basic and PHP. The original articles were quite old (written in 2002!) so this code may be quite outdated, but it still works.

Decimal to Hexadecimal

Visual Basic

output = Hex(number)

PHP

$output = sprintf("%x", $number);

Hexadecimal to Decimal

Visual Basic

decimal = Val("&H" & hexnumber)

PHP

sscanf($input, "%x", $decimal);

Decimal to Binary

Visual Basic

For i = 7 To 0 Step -1
  If n >= 2 ^ i Then
    n = n - (2 ^ i)
    output = output & "1"
  Else
    output = output & "0"
  End If
Next

PHP

$output = sprintf("%b", $number);

Binary to Decimal

Visual Basic

For i = Len(bin) To 1 Step -1
  If Mid(bin, i, 1) = "1" Then
    n = n + (2 ^ (Len(bin) - i))
  End If
Next

PHP

sscanf($input, "%b", $num);