Income refers to total profits (net income) after subtracting expenses from revenue. Below is a simple way of calculating total expenses from revenue, owner's equity, and income: Net income = End equity - Beginning equity (from the balance sheet) Total Expenses = Net Revenue - Net Income

Expenses are generally recorded on an accrual basis, ensuring that they match up with the revenues reported in accounting periods. Expenses are used to calculate net income. The equation to calculate net income is revenues minus expenses.

Simply add up all of your monthly fixed expenses, like rent or a mortgage payment, and your variable expenses, such as groceries and gas costs. Also factor in occasional but expected purchases, such as new tires. The resulting amount, assuming you aren't going to debt every month, is your cost of living.