Abstract A method using relative permeability curves is presented to determine in about 30 minutes by the use of a desk calculator and graphs the recovery vs. cumulative water-injected of linear and 5-spot waterfloods. The determinations for the linear model are nearly identical to, and for the 5-spot within an average of 2 percent of, those calculated by the electronic computer used in the Higgins and Leighton technique. The 5-spot results by the graphical method are also within an average of 5 percent of those for presently available experimental 5-spot waterfloods. The graphical method does not give, however, the time or rate of oil recovery. The procedure uses the fractional flow, or fw, curve from the relative permeability curves and uses Welge tangents to the fw curve. Cumulative water injection is calculated from the slopes of the tangents, and recovery is calculated using extension of tangents to fw=1 From these data, recovery vs. pore volumes injected for a linear waterflood are plotted.