摘自水木论坛

# coding:utf-8
# 个税起征点
startTax = 5000

def getNumberBeforeTax(month):
    # 计算当月及累计到当月的专项扣除的金额
    decreaseTaxYear = 0
    for i in range(1, month+1):
        decreaseTaxNumber = 0
        for key in specialTax.keys():
            #print key, specialTax.get(key)
            specialTaxMonth = 0
            if specialTax.get(key)[1]<=i<=specialTax.get(key)[2]:
                specialTaxMonth = specialTax.get(key)[0]

            decreaseTaxNumber += specialTaxMonth
            
        decreaseTaxYear += decreaseTaxNumber
    
    return decreaseTaxYear, decreaseTaxNumber

def getSalaryBeforeTax(month):
    # 计算当月月薪，累计到当月的年薪以及累积到当月的应税收入
    for i in range(1, month+1):
        salaryBaseMonth = 0
        salaryBaseYear = 0
        salaryTaxYear = 0
        for key in salaryBase.keys():
            if salaryBase.get(key)[1]<=month<=salaryBase.get(key)[2]:
                salaryBaseMonth = salaryBase.get(key)[0]
                salaryTaxYear += countBaseForTax(salaryBaseMonth)*i
                salaryBaseYear += salaryBase.get(key)[0]*(i-salaryBase.get(key)[1]+1)
            elif i>salaryBase.get(key)[2]:
                salaryBaseYear += salaryBase.get(key)[0]*(salaryBase.get(key)[2]-salaryBase.get(key)[1]+1)
        
    return salaryBaseMonth, salaryBaseYear, salaryTaxYear
        

def countBaseForTax(salaryMoney):
    # 根据月薪计算当月应税额
    if salaryMoney<=25401:
        return salaryMoney-salaryMoney*0.222-3
    else:
        return salaryMoney-25401*0.222-3

def countTax(moneyCount):
    # 计算个税额
    if moneyCount <= 36000:
        return 0.03*moneyCount
    
    elif 36000 < moneyCount <= 144000:
        return 0.1*moneyCount-2520
    
    elif 144000 < moneyCount <= 300000:
        return 0.2*moneyCount-16920
    
    elif 300000 < moneyCount <= 420000:
        return 0.25*moneyCount-31920
    
    elif 420000 < moneyCount <= 660000:
        return 0.3*moneyCount-52920
    
    elif 660000 < moneyCount <= 960000:
        return 0.35*moneyCount-85920
    
    else:
        return 0.45*moneyCount-181920
    

def countTT():
    print "-"*25
    #print "月份    ", '{0:^22}'.format("本月纳税额 "), '{0:^40}'.format("年度纳税额")
    print "月份 ", "本月纳税额 ", "年度纳税额"
    print "-"*25
    print "-"*25
    taxForThisYear = 0
    for i in range(1,13):
        moneyForTaxEach = getSalaryBeforeTax(i)[2]- getNumberBeforeTax(i)[0] - startTax*i
        taxForThisMonth = countTax(moneyForTaxEach)
        print '{0:<4}'.format(i), '{0:>8}'.format(round(taxForThisMonth-taxForThisYear,1)), '{0:>12}'.format(round(taxForThisMonth,1))
        taxForThisYear += taxForThisMonth-taxForThisYear

if __name__ == "__main__":
    # 专项扣除及起始月份，如某项无扣除，该项金额设置为0即可
    specialTax = {"childTaxCount" :(1000,1,12), # 子女
                  "houseFunding"  :(1000,1,12), # 房贷
                  "parentTax"     :(2000,1,12), # 赡养父母
                  "houseRental"   :(0,1,12), # 房租
                  "education"     :(0,1,12)}    #继续教育
    # 月薪及起始月份
    salaryBase = {"salaryPhase1":(30000,1,2),
                  "salaryPhase2":(33000,3,12)}
    # 计算每月因纳税额以及年底累计纳税额
    countTT()