Money guides

Short, practical guides to the decisions behind the calculators, with real numbers worked out for you.

• How PMI works

  What private mortgage insurance costs, the 80% and 78% rules for ending it, and FHA’s different rules.

• 15-year vs. 30-year mortgage

  Payment, total interest and equity at this week’s rates, and paying a 30-year loan early.

• Interest rate vs. APR

  Why fees make the APR higher, with a table of APRs by origination fee.