FAQ
Questions people ask before they trust a schedule
Short answers. If a number on your statement still disagrees after these, the statement wins.
How accurate is this mortgage amortization calculator?
For a U.S. fixed-rate loan, AmortSheet uses the standard level-payment formula and monthly simple interest rounded to cents. It should land within a dollar or two of a servicer’s P&I schedule when the principal, rate, term, and first-payment date match. It will not match a statement that includes escrow, a daily-interest product, or an ARM reset.
Does the schedule include taxes, insurance, or PMI?
No. This is principal and interest only. Escrow for taxes and insurance, mortgage insurance, and HOA dues are separate. That is why the monthly number here is often lower than the draft your bank takes.
If I pay extra, does my required monthly payment go down?
Usually not. Extra principal shortens the loan and cuts interest. The contractual P&I stays the same unless you request a recast (when the loan allows it) or refinance. AmortSheet models the common path: same bill, earlier payoff.
How do extra monthly and one-time payments work in this tool?
Extra monthly is added to principal every period after that month’s interest. A one-time extra is applied on the payment number you choose — payment 1 is the first due date. Both are capped so they cannot overshoot the remaining balance.
Is a biweekly plan better than a monthly extra?
A true biweekly plan sends 26 half-payments, which equals 13 monthly payments a year. The economic engine is that 13th payment, not the two-week calendar. You can get nearly the same result by adding monthly P&I ÷ 12 as extra principal. See the biweekly vs monthly guide.
Can I pay extra on FHA, VA, or USDA loans?
Generally yes. Government-backed loans typically allow prepayment without penalty. Recasts are less commonly offered than on conventional loans. Confirm with the servicer how they want extra principal labeled.
Do modern U.S. mortgages have prepayment penalties?
Most qualified mortgages originated in the last decade do not. Some non-QM, portfolio, and older notes still do. The note — not a blog post — is the authority. If a penalty exists, extra payments can cost more than they save.
Why doesn’t this match the payoff quote from my servicer?
Payoff quotes add per diem interest through the exact closing date, unpaid late fees, and sometimes escrow over/under. A schedule is a monthly forecast. Use a formal payoff letter when you sell or refinance.
Is this financial, tax, or lender advice?
No. AmortSheet is an educational calculator. It is not a lender, broker, or advisor, and it does not originate, service, or commit to any loan. See the disclaimer.
Do you store my loan numbers?
No. The math runs in your browser. Sharing a URL with query parameters will expose those figures to anyone who has the link; that is optional and local to the address bar.
More depth: how amortization works,extra payments,biweekly vs monthly.
Estimates only. AmortSheet models principal and interest on a U.S. fixed-rate mortgage. It does not include taxes, insurance, PMI, HOA dues, or lender fees, and it isnot lender advice, a loan offer, or a commitment to lend. Confirm figures with your servicer. Full disclaimer.