one ml of Lugols 5% will have 100mg of KI and 50mg of I2 for a total Iodine content of 125mg
And here's the comparison from Bobby's Health Shop --
Their 7% Lugol's -- 1 ml has 50 mg KI and 25 mg I2 for a total iodine content of 63 mg. This is half the iodine content of 5% Lugol's, so I'd call it 2-1/2% Lugol's.
Their 15% Lugol's -- 1 ml has 120 mg KI and 60 mg I2 for a total iodine content of 151 mg. This looks to be 6% Lugol's.
It's been proposed before that their labelling practice includes the percent of I2 + KI, whereas the usual label for Lugol's reflects only the percent of I2. That's why their numbers look so large and impressive, while their solution is weaker than implied.