Mortgage & money comparisons

Each page states a representative scenario, works out the numbers with the same math the calculators use, and gives a plain bottom line — then links you to the tools to run your own figures.

• 15- vs. 30-year mortgage — The 15-year saves a large amount of interest and builds equity fast; the 30-year keeps the payment low and flexible. The numbers on a $400,000 loan.
• 20% down vs. a smaller down payment — Putting 20% down avoids PMI and lowers the payment, but ties up cash. When a smaller down payment plus reserves is the smarter call.
• 529 plan vs. a taxable brokerage account — A 529 grows tax-free for qualified education costs; a taxable account is more flexible but loses ground to taxes along the way. The gap over 10 years.
• 529 plan vs. Coverdell ESA — Both grow tax-free for education costs. The real differences are the contribution cap, investment control, and how broadly each covers K-12 spending.
• ARM vs. fixed-rate mortgage — An adjustable-rate mortgage's lower starting rate is a real saving for the fixed years — worth it only if you will be gone before it adjusts.
• Biweekly vs. monthly mortgage payments — Paying half your mortgage every two weeks adds one extra payment a year and shaves years off the loan — but only if the servicer applies it right.
• Buying points vs. taking the higher rate — Discount points are prepaid interest that buy a lower rate. Whether they pay off comes down to one number: how long you keep the loan.
• Debt snowball vs. debt avalanche — The avalanche saves the most money; the snowball delivers wins sooner. How far apart they actually are, and how to choose.
• Extra payments vs. a shorter term — Committing to a 15-year loan locks in a lower rate; voluntarily overpaying a 30-year keeps flexibility. What the flexibility costs.
• Federal vs. private student loans — Federal loans carry a fixed rate set by law and built-in safety nets; private loans can undercut that rate for excellent credit but drop most of the protections.
• Pay off the mortgage vs. invest — A guaranteed return equal to your rate versus a higher but uncertain market return. How the gap changes with your mortgage rate.
• Refinance vs. recast — A refinance changes your rate and term for a few thousand in costs. A recast just re-amortizes after a lump sum for a small fee. When each fits.
• Renting vs. buying a home — Buying wins on a long enough horizon, but transaction costs make short stays a loser. What the break-even really depends on.