Each guide explains one idea, works an example with real arithmetic and links to the calculator that does the same math with your numbers. We are a calculator site, not a lender or adviser; where a rule comes from a regulator or the IRS, the guide links to the source.
Where to start
Buying your first home? Start with the 28/36 rule, which is how most lenders size a payment against your income, then read 15 vs 30-year mortgage to see what the term does to the payment and to the total interest. The affordability calculator runs both with your own income and debts.
Already have a loan? How mortgage interest is calculated shows why early payments are mostly interest and how an extra payment shortens the loan. Should I refinance for 1% walks through the break-even month once closing costs are counted, and the refinance break-even calculator does it for your quote.
Deciding what to do with spare cash? Pay off the mortgage or invest compares a guaranteed return equal to your rate with an uncertain market return, and is honest that the answer depends on your rate, your tax situation and how much risk you can stomach. What is escrow explains the taxes and insurance folded into your monthly payment and why it changes each year.
Building or putting less than 20% down? How construction loans work follows a build draw by draw, from interest-only payments to the mortgage after conversion, with the construction loan calculator doing the same math for your budget. Piggyback mortgages compares an 80/10/10 split with a single loan plus PMI over 5, 10 and 30 years.