Concentration as %

%w/v stands for percentage weight in volume which is grams in 100 ml:

To convert percent to milligram (mg):

Either multiply the percent strength by 10 or move the decimal point one space to the right. For example 1% lidocaine = 10 mg/ml

To convert milligram (mg) to percent:

Move the comma one space to the left. For example lignocaine 20 mg/ml = 2%