Equations are presented for determining the proportion of the total perimeter and area burned for a simple elliptically shaped fire for any specified range of Byram's fireline intensities. The same principles apply to any characteristic that is dependent on fireline intensity. Only three inputs are required: head-fire intensity; the elliptical shape factor; and the backfire spread rate. This last quantity is not required if it is assumed that the ignition point is at one focus of the ellipse. The spatial distributions produced have potential application to fire management.