On any given night of the year, over 2 million people will be staying at a space listed by Airbnb. The short-term rental app and website lists over 6 million homes, apartments, tree houses, castles and single private and shared rooms. Many of the listings are owned by people just like you: homeowners who want to make a supplemental income from a side-hustle.

How do you know how much your spare bedroom would be worth to someone visiting your area? Will it be enough to pay the mortgage or a couple of dinners-out during the week?

Airbnb makes it easy to see a projection for your space with a link on its website.

Simply go to Airbnb’s website and click on "Become a host" at the top of the page. You will prompted to enter your location and a couple of other details about your space such as whether you'll be renting out the entire place, a private or shared room. You'll also be asked how many guests can stay in the space.

It then makes a projection based on 15 rentals per month.

To get some idea of what to expect, I entered Charleston, South Carolina and found out a house that can host 4 guests can earn somewhere around $4,000 per month. A single-room for 2 people might allow me to charge enough to earn $3,000 a month. Listing a shared room for 1 person might bring in a little over $1,000 per month, again based on an expected occupancy of 15 days a month.

The tool is a little vague and there are many variables that influence what a person can charge per night. Availability or how many rental properties and hotel rooms are in the area, occupancy, and how many people travel to the area looking for an overnight stay are factors. Also playing a big part in determining a nightly rate are the reviews a short-term rental gets on the Airbnb website.

By filling out more information on the Airbnb website you can get a more accurate picture of what you might be able to make each month.