Your doctor needs to know certain numbers to judge your physical health, such as your weight, your blood pressure and your cholesterol levels.
Similarly, you need to know certain numbers to monitor your own financial health, including:
AFTER-TAX INCOME AND ‘MUST-HAVE’ EXPENSES
Your after-tax income is your gross income minus the taxes you pay (federal, state and local income taxes, plus Social Security and Medicare taxes). If you get a steady paycheck, you can use your latest pay stub to calculate this figure. Otherwise, check your most recent tax return.
Divide your after-tax income by the number of hours you