hmm I tried yours, but it just doesn't look right to me
/say $ratio(1000 10)
1000:0
/say $ratio(10 1000)
10:0
so I messed with it some more
Code:
alias ratio {
  var %1 = $1, %2 = $2
  if (%1 <= %2) { var %ratio = $calc(%2 / %1) $+ :1 }
  if (%1 > %2) { var %ratio = $calc(%1 / %2) $+ :1 }
  msg $active %ratio $+($chr(40),$round($calc((%1 / %2) * 100),0),$chr(37),$chr(41))
}


/ratio 1000 10
100:1 (10000%)
/ratio 10 1000
100:1 (1%)