Cumulative tax law: calculate how much tax you have paid in a year

Premise ：

Shanghai 、2021 Social security ceiling base in :31014, The proportion of individual payment is 10.5%( among , social security 8%, Medical fertility 2%, unemployment 0.5%). It does not take into account that the base is adjusted only in the middle of each year , We should use this base for the whole year , To calculate your personal income tax , Don't consider the year-end bonus 、 Stocks, etc .

First of all, I would like to present the results ：

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Python The code is as follows :

import sys
import os
import shutil
import time
import random
import subprocess
import getopt
import json
import xlrd
import xlwt

def get_config():
    with open('table.cfg', 'r') as f:
        return json.load(f)


config = get_config()
percent = config["social_insurance"]["shanghai"]["2021"]["percent"]
base_limit = config["social_insurance"]["shanghai"]["2021"]["base_limit"]
tax_stages = config["tax_stage"]
tax_rates = config["tax_rate"]
reductions = config["reduction"]


def create_sheet(f,table_name,try_count):
    if try_count <= 1:
        return
    try:
        sheet1 = f.add_sheet(table_name + '-' + str(11 - try_count),cell_overwrite_ok=True)
        return sheet1
    except Exception as e:
        return create_sheet(f,table_name,try_count-1)

def create_a_new_excel(excel_path,table_name,title_name,use_lists):
    table1_invalid_start_x = 1;
    table1_invalid_start_y = 2;
    max_buf_len = []
    if os.path.exists(excel_path):
        os.remove(excel_path)
    f = xlwt.Workbook(encoding='utf-8') # newly build excel

    font = xlwt.Font()
    font.bold = True
    borders = xlwt.Borders()
    borders.left = xlwt.Borders.THIN
    borders.right = xlwt.Borders.THIN
    borders.top = xlwt.Borders.THIN
    borders.bottom = xlwt.Borders.THIN
    alignment = xlwt.Alignment()
    alignment.horz = xlwt.Alignment.HORZ_CENTER  # horizontal direction 
    alignment.vert = xlwt.Alignment.VERT_TOP
    style1 = xlwt.XFStyle()
    style1.font = font
    #style1.borders = borders
    style1.alignment = alignment
    
    style2 = xlwt.XFStyle()
    style2.alignment.wrap = 1 # Word wrap 

    try:
        sheet1 = f.add_sheet(table_name,cell_overwrite_ok=True)
    except Exception as e:
        sheet1 = create_sheet(f,table_name,10)

    for item in range(0, len(title_name)):
        sheet1.write(1, item+table1_invalid_start_x, title_name[item],style=style1)
        max_buf_len.append(len(title_name[item]))
        sheet1.col(1).width = 256 * (max_buf_len[item])
 
    item = 0
    column_len = len(title_name)
    for use_list in use_lists:
        for column_index in range(0, column_len):
            if len(use_list[title_name[column_index]]) > max_buf_len[column_index]:
                max_buf_len[column_index] = len(use_list[title_name[column_index]])
            if max_buf_len[column_index] > 150:
                max_buf_len[column_index] = 150
            sheet1.col(column_index+table1_invalid_start_x).width = 256 * (max_buf_len[column_index] + 3)
            sheet1.write(table1_invalid_start_y + item, column_index+table1_invalid_start_x, use_list[title_name[column_index]],style2)
        item += 1
    f.save(excel_path)

test_title = [
    " Annual salary "," The social security accumulation fund is paid in total "," Total taxes paid "," Total after tax income "
]
user = {
    }



test_use_list = [

]

def calculate_tax(salary): #salary year
    if salary / 12 > base_limit:
        base = base_limit
    else:
        base = salary / 12
    
    insurance= base * 12 * percent / 100
    print(" Annual salary :%s" % str(salary))
    print(" The social security accumulation fund is paid in total :%s" % str(insurance))
    
    
    taxable_income = salary - insurance - 5000 * 12
    if taxable_income < 0:
        taxable_income = 0
    #print(" The total amount of tax to be paid :%s" % str(taxable_income))

    i = 0
    for tax_stage in tax_stages:
        if taxable_income < tax_stage:
            break
        i = i + 1
    tax = taxable_income * tax_rates[i] / 100 - reductions[i]
    print(" Total taxes paid :%s" % str(tax))
    after_tax = salary - tax - insurance
    print(" Total after tax income :%s" % str(after_tax))
    print("%s\t%s\t%s\t%s" %(str(salary), str(insurance), str(tax), str(after_tax)))
    
    user[" Annual salary "] = str(salary)
    user[" The social security accumulation fund is paid in total "] = str(insurance)
    user[" Total taxes paid "] = str(tax)
    user[" Total after tax income "] = str(after_tax)
    test_use_list.append(user.copy())

if __name__ == '__main__':
    print(str(sys.argv[0]) + " enter")
    curdir = os.getcwd()

    for i in range(6,101):  # 6-100w
        salary = i * 10000
        calculate_tax(salary)
    for i in range(1,51): # 110w - 500w
        salary = i*100000 + 1000000
        calculate_tax(salary)
   
    print(test_use_list)
    s_name = "1.xls"
    create_a_new_excel(s_name,"table1",test_title, test_use_list)

Configuration table :

{
    
	"social_insurance":
	{
    
		"shanghai":
		{
    
			"2021":
			{
    
				"percent":10.5,
				"base_limit":31014
			}
		}
	},
	"tax_stage":
	[
		36000,
		144000,
		300000,
		420000,
		660000,
		960000
	],
	"tax_rate":[3,10,20,25,30,35,45],
	"reduction":
	[
		0,2520,16920,31920,52920,85920,181920
	]
}

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（backup）
2021 Base and proportion of payment
2021 New personal income tax rate table

Premise :2021 year , The upper limit of social security accumulation fund in Shanghai is 31014, Suppose your annual salary is taxed according to your salary , Tax is not calculated according to the year-end bonus .
1、 If you 2021 Year is 100W Pay for , So this year, the social security accumulation fund has been paid close to 4W, Your personal income tax has been paid 25W., In a year 71w
2、 If you 2021 Year is 80W Pay for , So this year, the social security accumulation fund has been paid close to 4W, Your personal income tax has been paid 17.5W, In a year 58.5w
3、 If you 2021 Year is 60W Pay for , So this year, the social security accumulation fund has been paid close to 4W, Your personal income tax has been paid 11.5W, In a year 43.5w
4、 If you 2021 Year is 40W Pay for , So this year, the social security accumulation fund has been paid close to 4W, Your personal income tax has been paid 5.8W, In a year 30.2w