When you move, you don’t want to end up falling short on boxes, tape and other moving materials. That would make an already overwhelming day of moving worse. However, you don’t want to spend more than necessary and end up with a mountain of unused supplies either.

Rather than relying on guessing, there is a tool available that can help.

The National Association of Realtors (NAR) recommends the free packing calculator on Moving.com. You simply input some basic data about your home, such as the number of bedrooms, and it computes the sizes and number of boxes you need, along with a recommended list (with quantities) of other moving supplies.

The calculator not only helps you buy just what you need for your move, but it also reminds you of those packing supplies people often forget to purchase, such as colored markers, stretch wrap, and bubble wrap.

So, if you’re planning on moving in the coming months, check out this tool. And, keep in mind, there are many other tips and techniques available for making your sale and move go smoothly.