Investing Horizons · Tools

Monthly Expense Calculator for retirement planning and everyday budgets

See exactly where your money goes, compare it with your income, and find out how much is left to invest each month. The yearly total also tells you how big a retirement nest egg your lifestyle needs.

Show figures as

Monthly income

Monthly expenses

Left to invest

Thinking about retiring early? See the FIRE number for these expenses →

Income

Choose whichever number you already know.

Gross monthly income

Estimated tax rateFederal, state and FICA combined

Estimated take-home pay $0

Built by Justin Wiggins. This is an educational tool, not financial advice.

This monthly expense calculator for retirement planning starts with the number every retirement plan depends on: what your life actually costs. Add up what you spend, compare it with your take-home pay, and carry the yearly total straight into the FIRE Calculator.

How to use the Monthly Expense Calculator

Choose whether to enter your gross pay and a tax rate, or the take-home pay you already know.
Open each category and fill in what you spend. Use the period buttons to type weekly, biweekly, monthly or yearly amounts; everything is converted for you.
Check "Left to invest" at the top, then follow the FIRE Calculator link to see what your spending means for retiring early.

How this calculator works

Every amount you type is stored as a monthly figure. A weekly bill is multiplied by 52 and divided by 12, a biweekly bill by 26 and then 12, and a yearly bill is simply divided by 12. That's why switching between Weekly, Biweekly, Monthly and Yearly changes how your totals look, never what they are.

Income works one of two ways. If you know your take-home pay (what actually lands in your account), enter it directly. If you only know your gross pay (what you earn before anything is withheld), the calculator applies your estimated tax rate: gross × (1 − tax rate).

Spending is the sum of every category. Housing counts only the Homeowner list or the Renter list, never both. Negative amounts count as zero, the tax rate stays between 0% and 100%, and Left to invest is simply take-home pay minus spending.

For retirement planning, the yearly total is the number that matters. The FIRE Calculator link carries it in the part of the web address after the # sign, which browsers never send to a server, so your spending stays on your device.

A worked example

Say you're 58, your mortgage is paid off, and you want to know what retirement will really cost. You enter $6,200 a month in take-home pay, then your bills: property tax, insurance, upkeep and utilities add up to $950 a month, and healthcare runs $640.

Groceries are easier to think of by the week, so you switch to Weekly and type $150. Back on Monthly, that shows as $650. Add dining out, the car, a $300 travel fund and the rest, and your spending totals $3,150 a month, leaving $3,050 to invest.

Switch to Yearly and spending reads $37,800. Follow the FIRE Calculator link and, at a 4% withdrawal rate, that lifestyle needs a $945,000 nest egg. (These figures are illustrative, entered into this calculator for a made-up household.)

Methodology and sources

This calculator doesn't assume what you should spend. Every figure is yours, blank fields count as zero, and the example numbers it loads with are placeholders, not national averages. The tax rate is one blended estimate of federal, state and payroll taxes, not a tax calculation.

If you're unsure of your rate, the IRS Tax Withholding Estimator and your own pay stub are the best guides. To compare your spending with other households, including those headed by someone 65 or older, see the Bureau of Labor Statistics' Consumer Expenditure Surveys.

Last updated: October 2026

Frequently asked questions

How much will I spend in retirement?

It varies so much that your own numbers beat any rule of thumb. Some costs often fall, like commuting and saving for retirement itself, while others, especially healthcare and travel, can rise. Start with what you spend today, then adjust each category for the life you're planning.

How do I turn weekly or yearly costs into a monthly amount?

Multiply by how many times a year you pay it, then divide by 12. A $50 weekly cost is $50 × 52 ÷ 12, about $217 a month. This calculator does that for you when you switch the period buttons.

How do monthly expenses turn into a retirement savings goal?

Multiply your monthly spending by 12, then divide by a withdrawal rate you're comfortable with. At 4%, that's the same as multiplying your yearly spending by 25. The FIRE Calculator link does the math for you.

Should I budget with gross pay or take-home pay?

Take-home pay. Gross pay is what you earn before taxes and deductions; take-home pay is what actually lands in your account, so it's the money you can spend or invest.

What should I do with the money left over?

Common next steps are building an emergency fund, paying down high-interest debt and investing for retirement. The Pay It Down calculator and the Investment Simulator can help you weigh those.