This calculator provides an estimate and is for informational purposes only. Actual withholding may vary. Consult a tax professional for personalized advice.
Understanding Your Missouri Paycheck Taxes
Calculating your net pay involves understanding federal and state income taxes, as well as FICA taxes (Social Security and Medicare). This Missouri Paycheck Tax Calculator aims to provide a close estimate of these deductions.
Federal Income Tax Withholding
Federal income tax is progressive, meaning higher income is taxed at higher rates. The amount withheld from your paycheck depends on your:
Gross Pay: Your total earnings before deductions.
Pay Frequency: How often you are paid (weekly, bi-weekly, etc.).
Filing Status: Your tax classification (Single, Married Filing Jointly, Head of Household).
Number of Allowances: This represents deductions you claim on Form W-4, reducing the amount of tax withheld. More allowances generally mean less tax withheld.
The IRS uses Publication 15-T, "Federal Income Tax Withholding Methods," to determine the correct withholding. This calculator uses simplified methods based on common tax tables and formulas.
Missouri State Income Tax
Missouri has a flat tax rate for state income tax, but the actual amount withheld is influenced by:
Gross Pay: Your total earnings.
Missouri Filing Status: Single, Married, or Head of Household, similar to federal status but with state-specific adjustments.
Number of Allowances (MO Form MO W-4): Like federal allowances, these reduce the amount of state income tax withheld.
Missouri's income tax rates can change, and specific tax tables are used by employers for accurate withholding.
FICA Taxes (Social Security and Medicare)
These are federal payroll taxes that fund Social Security and Medicare. They are calculated on gross pay up to certain limits:
Social Security Tax: Currently 6.2% on earnings up to an annual wage base limit (this limit changes yearly).
Medicare Tax: Currently 1.45% on all earnings, with no wage base limit. Additional Medicare Tax may apply to higher earners.
Both Social Security and Medicare taxes are capped annually for Social Security, but not for Medicare.
How the Calculator Works (Simplified)
This calculator estimates federal income tax based on standardized withholding tables and the information you provide. It applies the current Missouri state income tax rate and withholding adjustments. FICA taxes are calculated at their standard rates.
Disclaimer: Tax laws are complex and subject to change. This tool is for educational and estimation purposes. For precise figures and tax advice, please consult a qualified tax professional or refer to official IRS and Missouri Department of Revenue resources.
function calculateTaxes() {
var grossPay = parseFloat(document.getElementById("grossPay").value);
var payFrequency = document.getElementById("payFrequency").value;
var filingStatus = document.getElementById("filingStatus").value;
var allowances = parseInt(document.getElementById("allowances").value);
var moFilingStatus = document.getElementById("moFilingStatus").value;
var moAllowances = parseInt(document.getElementById("moAllowances").value);
// — Input Validation —
if (isNaN(grossPay) || grossPay < 0) {
alert("Please enter a valid Gross Pay.");
return;
}
if (isNaN(allowances) || allowances < 0) {
alert("Please enter a valid number of Federal Allowances.");
return;
}
if (isNaN(moAllowances) || moAllowances < 0) {
alert("Please enter a valid number of Missouri Allowances.");
return;
}
// — Constants and Rates —
var SOCIAL_SECURITY_RATE = 0.062;
var MEDICARE_RATE = 0.0145;
var SOCIAL_SECURITY_WAGE_BASE_2023 = 160200; // For 2023, use current year as needed.
var MISSOURI_TAX_RATE_SINGLE_MARRIED = 0.0495; // Example flat rate, subject to change
var MISSOURI_TAX_RATE_HEAD_OF_HOUSEHOLD = 0.0495; // Example flat rate, subject to change
// — Calculate Pay Period Adjustments —
var payPeriodMultiplier = 1;
if (payFrequency === "weekly") {
payPeriodMultiplier = 52;
} else if (payFrequency === "biweekly") {
payPeriodMultiplier = 26;
} else if (payFrequency === "semimonthly") {
payPeriodMultiplier = 24;
} else if (payFrequency === "monthly") {
payPeriodMultiplier = 12;
}
var annualGrossPay = grossPay * payPeriodMultiplier;
// — Calculate FICA Taxes —
var socialSecurityTaxablePay = Math.min(annualGrossPay, SOCIAL_SECURITY_WAGE_BASE_2023);
var socialSecurityTax = socialSecurityTaxablePay * SOCIAL_SECURITY_RATE / payPeriodMultiplier;
var medicareTax = grossPay * MEDICARE_RATE;
// — Calculate Federal Income Tax (Simplified based on 2023 W-4 withholding tables logic) —
// This is a simplified approximation. Real withholding uses IRS tables.
var federalTaxableIncome = annualGrossPay;
var standardDeduction = 0;
if (filingStatus === "single") {
standardDeduction = 13850; // 2023 standard deduction for single
} else if (filingStatus === "married") {
standardDeduction = 27700; // 2023 standard deduction for married filing jointly
} else if (filingStatus === "headOfHousehold") {
standardDeduction = 20800; // 2023 standard deduction for head of household
}
// Reduce taxable income by standard deduction and allowances (simplified per allowance value)
var federalDeduction = standardDeduction + (allowances * 1000); // Rough estimate for allowance value
federalTaxableIncome = Math.max(0, annualGrossPay – federalDeduction);
// Apply simplified progressive tax brackets (Example rates for 2023)
var federalTaxAnnual = 0;
if (filingStatus === "single") {
if (federalTaxableIncome <= 11000) federalTaxAnnual = federalTaxableIncome * 0.10;
else if (federalTaxableIncome <= 44725) federalTaxAnnual = (11000 * 0.10) + ((federalTaxableIncome – 11000) * 0.12);
else if (federalTaxableIncome <= 95375) federalTaxAnnual = (11000 * 0.10) + (33725 * 0.12) + ((federalTaxableIncome – 44725) * 0.22);
else if (federalTaxableIncome <= 182100) federalTaxAnnual = (11000 * 0.10) + (33725 * 0.12) + (50650 * 0.22) + ((federalTaxableIncome – 95375) * 0.24);
else if (federalTaxableIncome <= 231250) federalTaxAnnual = (11000 * 0.10) + (33725 * 0.12) + (50650 * 0.22) + (86725 * 0.24) + ((federalTaxableIncome – 182100) * 0.32);
else if (federalTaxableIncome <= 578125) federalTaxAnnual = (11000 * 0.10) + (33725 * 0.12) + (50650 * 0.22) + (86725 * 0.24) + (49150 * 0.32) + ((federalTaxableIncome – 231250) * 0.35);
else federalTaxAnnual = (11000 * 0.10) + (33725 * 0.12) + (50650 * 0.22) + (86725 * 0.24) + (49150 * 0.32) + (346875 * 0.35) + ((federalTaxableIncome – 578125) * 0.37);
} else if (filingStatus === "married") {
if (federalTaxableIncome <= 22000) federalTaxAnnual = federalTaxableIncome * 0.10;
else if (federalTaxableIncome <= 89450) federalTaxAnnual = (22000 * 0.10) + ((federalTaxableIncome – 22000) * 0.12);
else if (federalTaxableIncome <= 190750) federalTaxAnnual = (22000 * 0.10) + (67450 * 0.12) + ((federalTaxableIncome – 89450) * 0.22);
else if (federalTaxableIncome <= 364200) federalTaxAnnual = (22000 * 0.10) + (67450 * 0.12) + (101300 * 0.22) + ((federalTaxableIncome – 190750) * 0.24);
else if (federalTaxableIncome <= 462500) federalTaxAnnual = (22000 * 0.10) + (67450 * 0.12) + (101300 * 0.22) + (173450 * 0.24) + ((federalTaxableIncome – 364200) * 0.32);
else if (federalTaxableIncome <= 693750) federalTaxAnnual = (22000 * 0.10) + (67450 * 0.12) + (101300 * 0.22) + (173450 * 0.24) + (98300 * 0.32) + ((federalTaxableIncome – 462500) * 0.35);
else federalTaxAnnual = (22000 * 0.10) + (67450 * 0.12) + (101300 * 0.22) + (173450 * 0.24) + (98300 * 0.32) + (231250 * 0.35) + ((federalTaxableIncome – 693750) * 0.37);
} else if (filingStatus === "headOfHousehold") {
if (federalTaxableIncome <= 14750) federalTaxAnnual = federalTaxableIncome * 0.10;
else if (federalTaxableIncome <= 59850) federalTaxAnnual = (14750 * 0.10) + ((federalTaxableIncome – 14750) * 0.12);
else if (federalTaxableIncome <= 95350) federalTaxAnnual = (14750 * 0.10) + (45100 * 0.12) + ((federalTaxableIncome – 59850) * 0.22);
else if (federalTaxableIncome <= 182100) federalTaxAnnual = (14750 * 0.10) + (45100 * 0.12) + (35500 * 0.22) + ((federalTaxableIncome – 95350) * 0.24);
else if (federalTaxableIncome <= 231250) federalTaxAnnual = (14750 * 0.10) + (45100 * 0.12) + (35500 * 0.22) + (86750 * 0.24) + ((federalTaxableIncome – 182100) * 0.32);
else if (federalTaxableIncome <= 578125) federalTaxAnnual = (14750 * 0.10) + (45100 * 0.12) + (35500 * 0.22) + (86750 * 0.24) + (49150 * 0.32) + ((federalTaxableIncome – 231250) * 0.35);
else federalTaxAnnual = (14750 * 0.10) + (45100 * 0.12) + (35500 * 0.22) + (86750 * 0.24) + (49150 * 0.32) + (346875 * 0.35) + ((federalTaxableIncome – 578125) * 0.37);
}
var federalTax = federalTaxAnnual / payPeriodMultiplier;
// — Calculate Missouri State Income Tax (Simplified) —
// Missouri has a flat tax rate, but withholding tables are complex.
// This is a simplified estimate based on gross pay and allowances.
var moTaxableIncome = grossPay; // Simplified approach
var moStandardDeduction = 0;
var moPersonalExemption = 0;
if (moFilingStatus === "single") {
moStandardDeduction = 1260; // Example, can vary
moPersonalExemption = 2100; // Example, can vary
} else if (moFilingStatus === "married") {
moStandardDeduction = 2520; // Example, can vary
moPersonalExemption = 4200; // Example, can vary
} else if (moFilingStatus === "headOfHousehold") {
moStandardDeduction = 2520; // Example, can vary
moPersonalExemption = 4200; // Example, can vary
}
var moTotalDeductions = moStandardDeduction + (moAllowances * 1000); // Rough allowance adjustment
var moTaxablePay = Math.max(0, moTaxableIncome – moTotalDeductions – moPersonalExemption);
var moTax = moTaxablePay * MISSOURI_TAX_RATE_SINGLE_MARRIED; // Using example flat rate
// — Calculate Net Pay —
var totalDeductions = socialSecurityTax + medicareTax + federalTax + moTax;
var netPay = grossPay – totalDeductions;
// — Display Results —
document.getElementById("result-value").innerText = "$" + netPay.toFixed(2);
document.getElementById("federalTaxesPaid").innerText = "Federal Tax: $" + federalTax.toFixed(2);
document.getElementById("moTaxesPaid").innerText = "Missouri Tax: $" + moTax.toFixed(2);
document.getElementById("socialSecurityPaid").innerText = "Social Security: $" + socialSecurityTax.toFixed(2);
document.getElementById("medicarePaid").innerText = "Medicare: $" + medicareTax.toFixed(2);
}