Income

Add any child support or spousal support you'll receive. Add to that any disability or unemployment compensation, pension payment, public assistance, or social security.

Add any interest, dividends, royalties, or rental income, and any distributions you receive from trusts or estates.

Income Taxes

Now before you start spending all your income, think about the taxes you'll pay on it. The easy way to do it is to use your pay stub, but remember that the truest figures on your taxes come from your actual tax returns. That's because they're not skewed by any overwitholding or underwithholding you or your spouse might be doing on your paycheck. If you already have copies of your tax returns, great. If not, you can order copies from the IRS.

Make sure you deduct for FICA (Social Security) and Medicare. You'll need to deduct state and local income taxes as well as any tax you pay for unemployment insurance.

You probably already know by now that there's all kinds of other information available here about taxes if you want to get into it now.

What's left is the income you can use. You're ready now to look at your expenses.