Its hard to figure out an exact number, but I'm sure the government could determine an approximation. Lets take our $10 per hour minimum wage. Thats about $20,000 a year. If rent is $1,000 a month that is $12,000 on rent. So $8,000 left. But some of that goes to taxes, transportation, and then lets talk about healthcare. For a family healthcare premiums can cost between $15,000 and $20,000, for individuals its more like $5,000 to $8,000. The employer can pay most of that but it depends on how good the healthcare plan is. And then you have to consider out of pocket.
If we had a $15 per hour minimum wage that would be a $30,000 income which makes life more affordable. I'd support between a $12 and $15 minimum wage depending on the cost of living.