How do you compute Philippine tax refund?

Try to compute your tax, that is your basic income times number of months you have stayed with the company less SSS, Philhealth and Pag-ibig remittances times the number of months you used before then subtract your exemptions. Now, you have your taxable income, looked on the tax bracket that correspond to it,anything over the starting bracket needs to be multiplied to the percentage of the bracket plus the amount before the percentage. It is now your income tax for the year. Compare it with the amount of tax deducted in your salary times the number of months it is deducted to you at the start of the year (this corresponds to the tax you have paid for the year). The answer to this less the income tax means either your tax refund/rebate or tax that needs to be paid.