What is 123 percent as a decimal?

No such value as '123%' in maths. 100% is totality.

However to convert 123% to a decimal. Remember the percent sign (%) means 'over one hundred'.

Hence 123/100 = 1.23 as a decimal.

NB when you read such figures as '200%' , it is totally incorrect, as menetioned above 100% is totality.

The author of suchg as statement should say it has 'doubled', increased twice(two times)', or multiplied by '2'.