The Wall Street Journal's Personal Finance guru, Jonathan Clements, recommends this financial calculator website.  The sheer volume of financial calculators it offers is amazing!  If you're planning your finances for the new year, you have got to check out this site.  Calculators useful to families include:

• Home Budget Analyzer
• Refinance Breakeven
• Checkbook Balancer
• Should my Spouse Work?
• 401k Savings Calculator
• Roth 401(k) or Traditional 401(k)?
• Auto Lease vs. Buying
• Life Insurance calculators

See related family finance tips on websites for monitoring your budget, On-Ramping, and free online checkbooks too.