function toggleHourlyInput() {
var freq = document.getElementById("payFrequency").value;
var hourlyFields = document.getElementById("hourlyFields");
if (freq === "hourly") {
hourlyFields.classList.remove("hidden");
} else {
hourlyFields.classList.add("hidden");
}
}
function calculateMonthlyIncome() {
var freq = document.getElementById("payFrequency").value;
var amount = parseFloat(document.getElementById("incomeAmount").value);
var taxRate = parseFloat(document.getElementById("taxRate").value) || 0;
var hoursPerWeek = parseFloat(document.getElementById("hoursPerWeek").value) || 0;
if (isNaN(amount) || amount <= 0) {
alert("Please enter a valid income amount.");
return;
}
var grossAnnual = 0;
var grossMonthly = 0;
if (freq === "annual") {
grossAnnual = amount;
grossMonthly = amount / 12;
} else if (freq === "hourly") {
grossAnnual = amount * hoursPerWeek * 52;
grossMonthly = grossAnnual / 12;
} else if (freq === "weekly") {
grossAnnual = amount * 52;
grossMonthly = grossAnnual / 12;
} else if (freq === "biweekly") {
grossAnnual = amount * 26;
grossMonthly = grossAnnual / 12;
}
var annualTax = grossAnnual * (taxRate / 100);
var netAnnual = grossAnnual – annualTax;
var netMonthly = netAnnual / 12;
document.getElementById("grossMonthly").innerText = "$" + grossMonthly.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById("netMonthly").innerText = "$" + netMonthly.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById("grossAnnual").innerText = "$" + grossAnnual.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById("annualTax").innerText = "$" + annualTax.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById("results").style.display = "block";
}
Understanding Your Monthly Income: A Complete Guide
Whether you are applying for a mortgage, creating a household budget, or negotiating a new job offer, knowing your exact monthly income is essential. While most employers discuss pay in terms of annual salary or hourly wages, the majority of our bills—rent, utilities, and subscriptions—are paid on a monthly basis.
How to Calculate Monthly Income
The method used to calculate your monthly earnings depends entirely on how you are paid. Because there are not exactly four weeks in every month (except February), simply multiplying a weekly check by four will result in an underestimation of your true annual earnings.
1. From Annual Salary
This is the most straightforward calculation. If you have a fixed annual salary, you simply divide the total by 12 months.
Formula:Annual Salary / 12 = Monthly Gross Income
2. From Hourly Wages
To find the monthly average for hourly work, you must first determine the annual total based on the number of hours worked per week, then divide by 12.
Formula:(Hourly Rate × Hours Per Week × 52 Weeks) / 12 = Monthly Gross Income
3. From Bi-Weekly Pay
Many employees are paid every two weeks (26 pay periods per year). To calculate the monthly average, multiply the gross amount of one check by 26 and divide by 12.
Formula:(Bi-Weekly Check × 26) / 12 = Monthly Gross Income
Gross vs. Net Monthly Income
It is vital to distinguish between these two figures:
Gross Monthly Income: Your total earnings before taxes, insurance, and retirement contributions are deducted. This is the figure banks usually look at for loan approvals.
Net Monthly Income: Also known as "take-home pay." This is what actually hits your bank account. For accurate budgeting, always use your net income.
Real-World Example
Let's look at an employee named Sarah who earns $30 per hour and works 40 hours per week with a 20% total tax rate.
Weekly Gross: $30 × 40 = $1,200
Annual Gross: $1,200 × 52 = $62,400
Monthly Gross: $62,400 / 12 = $5,200
Monthly Tax (20%): $5,200 × 0.20 = $1,040
Monthly Net Income: $5,200 – $1,040 = $4,160
Why Use a Monthly Income Calculator?
Using a dedicated calculator helps eliminate the "extra paycheck" confusion. If you are paid bi-weekly, two months out of the year you will receive three paychecks instead of two. A monthly income calculator smooths these fluctuations out to give you an accurate average for long-term financial planning.