Simulated marginal tax rates involve complex calculations of simulating future (uncertain) incomes and mimicking corporate tax code. This paper develops two algorithms to calculate simulated marginal tax rate. The codes have been developed to forecast future taxable income of Indian companies and their Marginal Tax Rates (MTR) using Monte Carlo simulation in MATLAB. Loss carry forward and minimum alternate tax rules have been incorporated in both the algorithms. Further, a change is made in both the algorithms to incorporate loss carry backward feature to suit the needs of the country where such laws are applicable. The 10000 simulations in MATLAB suggest that MTR is company specific and it is dependent on the income pattern of the company. The MTR increases when loss carry backward rule is applied. In cases where the company actually pays zero tax in a year due to incurred losses, it is found that even in such cases MTR may be non zero. It is found that there is enough cross sectional and time series variations in MTR, therefore, the effect of tax rates on various policy issues of government and companies can be studied by taking MTR as an effective proxy for tax rates.