Updated · Built and checked by the PlinzoTools team, formulas tested against published sources
Calculate your monthly budget surplus or shortfall from income and total expenses.
This tool compares your monthly take-home income against your total monthly expenses, showing what's left over (or how far over budget you are) and that surplus as a percentage of income -- a quick monthly budget health check.
Enter your monthly take-home income and total monthly expenses. Your remaining amount and savings rate appear instantly.
The calculator subtracts total monthly expenses from monthly take-home income. A positive number is money left over and is shown in green as a surplus. A negative number is shown in red as an overspend. The percentage next to it is that remainder divided by your income, so a surplus reads as a savings rate and a shortfall reads as a negative percentage. If income is zero or less, the percentage is shown as zero rather than an undefined value.
Remaining = income - expenses. Savings rate = remaining / income x 100.
Suppose your take-home pay is $4,000 a month and your expenses total $3,200. You have $800 left, which is 20 percent of income. Now suppose your income is $3,000 and your expenses are $3,400. The result is negative $400, or about negative 13.3 percent, meaning you are spending more than you earn and the gap must be covered by savings, credit or a change in spending. Try a middle case: $4,000 income and $3,900 expenses leaves $100, or 2.5 percent. That is technically positive, but it leaves almost no buffer for a surprise bill.
A budget is only as accurate as its expense figure, and people commonly undercount. To build a reliable total, work through the following.
Bank and card statements from the past three months are the best source. Guessing from memory almost always produces a total lower than reality.
The income field expects the amount that actually reaches your account after taxes, retirement contributions and payroll deductions. Entering your gross salary will make your surplus look larger than it is. If your income varies, for example with commissions, gig work or seasonal hours, use a conservative average or your lowest typical month so the plan holds up in slower periods.
There is no single correct savings rate; it depends on your goals, debts, family situation and cost of living. Some people use rules of thumb that divide income between needs, wants and saving, but these are only starting points, not requirements. A more useful approach is to decide what the surplus is for: an emergency fund, paying down high-interest debt, or a specific goal. If the result is negative, look first at the largest line items, since trimming a large expense usually does more than eliminating several small ones.
Because this tool works from one expenses figure, it cannot tell you where the money goes. Treat it as a quick health check, then use a category list or your bank's spending reports to dig into the details. It also does not include one-time windfalls, taxes owed at year end or investment growth. For personalized advice about debt, taxes or investing, a licensed financial professional is the right resource.
No -- this tool works from a single total-expenses figure for a quick surplus/shortfall check. Track category-by-category spending separately if you want a detailed breakdown.
Generally no. If you count savings as an expense, the leftover figure will understate what you are really setting aside. Enter only spending, and treat the remainder as what is available to save.
Use a conservative figure, such as your average of the lowest few months. That way the surplus you see is one you can count on rather than one that only appears in good months.
A negative percentage means expenses exceed income for the month. The gap has to come from savings, credit or reduced spending, so it is worth reviewing your largest expenses.
Divide each annual bill by 12 and add that amount to your monthly total. This spreads the cost evenly so a large insurance or registration payment does not create a surprise shortfall.
Reference: Consumer Financial Protection Bureau