When predicting fire behavior in the field, it is desirable to be able to obtain the required input information with a minimum of special equipment. This article tells how to estimate slope (percent) using materials in a belt weather kit. This method can be used on wildfires by fire behav­ior analysts, field observers, and strike team leaders. Those who are monitoring fires that are not receiving full suppression action, such as prescribed fires in wilder­ness, will find it especially useful.