In the thesis, the effects of blade number on aircraft propellers was calculated and analyzed using a simplified Blade Element momentum theory implemented on Microsoft Excel. The calculated results include Thrust, Torque, Thrust Coefficient, Power Coefficient, Efficiency for a 2,3, and 4-blade configuration across 5 different advance ratios (J = 0.3, 0.6, 0.9, 1.2, 1.5). Despite some limitations(e.g. Axial induction not being iterated to full convergence, Blade interference not being considered, constant chord distribution), the the results are useful for comparing the configurations. The trends are reliable and verified. The absolute numbers should be treated as approximate.