It may not be what you want to hear, but how much rent to charge your adult children living at home does depend on a few factors:1. What can the adult child afford? If they’re living at home, they probably can’t afford market rent.2. Why is the adult child living at home? Are they going to school? If so, you may want to charge less rent than if they are working.3. How long will they be living at home? Some parents will charge little to no rent for up to three months while the adult child gets back on his or her feet after a crisis like a divorce or a job loss, then start charging rent.So, you need to talk about what’s right for your family. Most important is that adult children living at home cover any additional expenses they add to the household – higher heating bills, extra grocery costs, more gas for the car, and so on. Working out a family budget is an important step that allows you to see what the adult child’s impact is and how they will pay for it.If the adult child is totally unable to pay rent, you may consider allowing them to contribute their labor instead. Adult children living at home should always be responsible for some standard chores around the house (like cleaning their room, doing their own laundry, and cooking some meals), but you could add some extra chores — like painting the house, cleaning the gutters, or helping with renovations, for example — that they could do to help “pay” for their stay.And most importantly, be sure to set a timeline for when the adult children living at home will leave. No matter how much rent they are paying, things will start to get uncomfortable if there is no plan for the adult child to get out on their own.