Cubic magnetocrystalline anisotropy constants, K1 and K2, for Fe1-xGax alloys were measured using magnetization curves with x = 0.05, 0.125, 0.14, 0.18 and 0.20. Thin circular {110} disks with all <100>, <110> and <111> in the plane of the disk were used to measure K1 and K2. K1 was also measured with {100} circular disks. K1 for 5 at% Ga content has been found to be larger than that of pure Fe. K1 and K2 both drops gradually till 18 % Ga substitution. Then there is a sharp drop in the magnitude of both the constants. <110> and <111> directions were magnetically equivalent for all the compositions considered for this study resulting in K2 to be equal to 9K1/4. A calculation of anisotropy energy density verifies this result. Magnitude of K1 measured from both {110} and {100} disks were reasonably consistent.