Calculating _real_ income tax percentage

calculate.js

// income tax
const base_income = // annual income before any tax
const federal_tax_rate = // 0.xx format
const state_tax_rate = // 0.xx format
// property tax
const monthly_rent = // dollar amount per month
const property_tax_rate = 0.18 // in new jersey at least
// medical tax
const monthly_health_insurance = // dollar amount per month
// consumption tax
const state_sales_tax = // 0.xx format
const income_spent_on_goods = // estimate of how much you spend on consumables as opposed to save or invest.
// if you're not sure, take a look at your `income_after_forced_taxes` to get an idea of how much total money you had available.
// education tax
const cost_of_education = // the total cost of your education
const annual_impact = 0.02 // this is an estimate as to how much that money will impact your income on average over your life.
// represented in 0.xx format. feel free to modify but i think it's a good starting point.

const real_income = base_income - base_income * (federal_tax_rate + state_tax_rate)
const annual_property_tax = monthly_rent * 12 * property_tax_rate
const annual_medical = monthly_health_insurance * 12
const annual_education = cost_of_education * annual_impact
const income_after_forced_taxes = real_income - annual_property_tax - annual_medical - annual_education

const real_base_tax_rate = (base_income - income_after_forced_taxes) / base_income
const real_leftover_cash = income_after_forced_taxes - (
    (monthly_health_insurance * 12) +
    (monthly_rent * 12) +
    (cost_of_education * annual_impact)
)

const sales_tax_paid = income_spent_on_goods * state_sales_tax

const final_total_income_tax = (base_income - (income_after_forced_taxes - sales_tax_paid) ) / base_income
const readable_total = ` ${('' + final_total_income_tax * 100).slice(0,5) + '%'}`

console.log(`in this world nothing can be said to be certain, except death and${readable_total} taxes.`)