Know your mortgage number before you sign.

We use the standard amortization formula: the loan amount is spread over the term so that every payment covers that month's interest plus a slice of principal. Early payments are mostly interest; later payments are mostly principal. A $400,000 loan at 6.5% for 30 years works out to $2,528.27 a month — a handy figure to check any calculator against.

Lenders bundle extras into your monthly bill: property taxes, homeowners insurance, and PMI if your down payment is under 20%. Those escrow items can easily add $300–$800 a month on top of principal and interest.

Yes. You pay a higher monthly amount, but the rate is usually lower and the balance falls twice as fast, so total interest often drops by more than half compared with a 30-year term.

It is the guideline most lenders start from: no more than 28% of your gross monthly income on housing costs (the front-end ratio), and no more than 36% on housing plus all other monthly debts (the back-end ratio). Many lenders allow higher ratios with a strong credit score, but staying near these numbers keeps your budget comfortable.

Almost never. The maximum ignores repairs, utilities, childcare, savings and fun. Many buyers are happiest spending 10–20% below the calculator's ceiling.

It is how many months of savings it takes to earn back the closing costs. If refinancing saves $150 a month and costs $6,000, you break even at month 40. Moving or refinancing again before then means the switch cost you money.

Because a new 30-year term restarts the clock. Paying a smaller amount for many more years can cost more in total interest than finishing your current loan sooner.

The earlier money hits the principal, the more interest it cancels — so monthly top-ups usually beat a single yearly payment of the same total. The difference is modest, though; the best plan is the one you will actually stick to.

Paying extra earns a guaranteed return equal to your mortgage rate, with no tax on the "gain". Investing may earn more over decades but carries risk. Many people split the difference.

Once your balance falls to 80% of the home's original value (20% equity), you can ask your servicer in writing to cancel PMI. At 78% of the original value (22% equity) it must be removed automatically on a current loan, under US federal rules for most conventional mortgages.

No — PMI protects the lender, not you. It simply makes the lender willing to offer the loan with a smaller down payment.

Buying has heavy upfront costs and most early payments go to interest, so renting usually wins for short stays. The longer you stay, the more principal you repay and the more appreciation works for you — buying typically pulls ahead somewhere between years five and seven.

US home prices have averaged roughly 3–4% a year over long periods, close to general inflation. Try 0% and 5% as pessimistic and optimistic cases to see how sensitive your decision is.

No. Most first-time buyers put down far less — the US median is under 10%. The trade-off is PMI and a higher payment. Run the PMI calculator above to see what a smaller down payment truly costs each month.

Keep an emergency fund intact. A slightly larger mortgage is much easier to handle than a surprise repair bill with no cash behind it.

Under 36% is the classic healthy zone and keeps most loan options open. Between 37% and 43% is workable for many lenders. Above that, approval gets harder and rates get worse — paying down a card or a car loan before you apply can move you a full band.

Pay off the smallest debts completely rather than spreading money across all of them. Removing a payment entirely lowers your monthly debt total, which is what the ratio measures.

There are 26 two-week periods in a year, so 26 half-payments equal 13 monthly payments — one full extra payment annually, all of it going to principal. Over a 30-year loan that typically cuts four to six years off the term.

The buyer pays most of them, but it is negotiable. In a buyer's market, sellers sometimes offer a credit toward closing costs; you can also ask the lender about credits in exchange for a slightly higher rate.

Sometimes. Some lenders offer "no-closing-cost" loans that fold the fees into a higher interest rate instead. You pay less upfront but more over the life of the loan — run both versions through the refinance-style math above to compare.