Calculators for loans, debt and savings
Each one answers one question with a schedule you can save. Nothing you type leaves your device.
Reviewed by Victor Yuki Matusita on . First published .
Loans, homes and debt
Mortgage calculator
Your monthly payment with taxes, insurance, PMI and HOA.
Personal loan calculator
The payment, the interest and the APR with an origination fee.
Auto loan calculator
What a car loan costs a month, with trade-in, taxes and fees.
Refinance calculator
Whether refinancing pays off, and in which month it breaks even.
Home affordability calculator
How much house fits your income, with the 28% and 36% rules of thumb.
Loan amortization calculator
The whole schedule of a loan: principal, interest and balance by payment.
Credit card payoff calculator
How long a card takes to pay off, or the payment for a target date.
Debt payoff calculator
Snowball against avalanche for up to 10 debts, with an extra payment.
Debt consolidation calculator
Your debts now against one new loan: payment, interest and time.
Rent vs buy calculator
Your net worth renting and buying, and the year buying catches up.
Savings and interest
Compound interest calculator
How a balance grows with monthly deposits and any compounding.
Savings goal calculator
The monthly deposit for a goal, or how long a deposit takes.
Simple interest calculator
Interest on a principal for years, months or days.
APR to APY calculator
A yearly rate turned into APY, or back, for any compounding.
Calculators for one question
| Calculator | What it answers |
|---|---|
| Mortgage with extra payments | The months and interest an extra payment saves on a mortgage. |
| Biweekly mortgage calculator | Half the payment every two weeks against the monthly payment. |
| 15-year vs 30-year mortgage | The two terms side by side: payment, interest and the difference. |
| Balloon loan calculator | The payment of a balloon loan and what is left due at the end. |
Guides with the numbers worked out
- 15-year vs 30-year mortgage: the real cost: What the shorter term costs a month and saves in interest, rate by rate.
- Snowball vs avalanche, with numbers: The two ways to pay off debts, run on the same four debts.
- How extra payments shorten a mortgage: What a little more each month does to the term and the interest.
- Refinancing: find your break-even month: Two ways to count the break-even, and why they can disagree.
- Rent vs buy: when buying starts to pay off: The year buying catches up with renting, and what moves it.
How these calculators work
Every calculator here runs in your browser. You type the numbers, including the interest rate: the value a field starts with is an example, not a rate anyone is offering you. The result changes as you type, and you can open the full schedule, save it as a PDF or a CSV, or copy a link that keeps your numbers after the #.
All of them work in cents, the way a lender does. The interest of each month is rounded to the cent and the last payment closes the balance, so the schedule you download adds up exactly. The engines were checked against an independent oracle built on numpy-financial and against worked examples from the Consumer Financial Protection Bureau.
The formula behind the loan calculators
A fixed-rate loan has the same payment every month: M = P × r × (1 + r)^n ÷ ((1 + r)^n − 1), where P is the amount borrowed, r is the yearly rate divided by 12 and n is the number of payments. Each payment first covers the month’s interest (the balance times r) and the rest lowers the balance.
The saving calculators run the same month-by-month loop the other way round: each month adds the interest on the balance and your deposit.
What every calculator assumes
- The rate you type stays the same for the whole period.
- Interest is worked out once a month and rounded to the cent, half up.
- Taxes, deductions and fees appear only where a field asks for them; rules that change by state or every year are fields you fill in, never tables built into the page.
A worked example
The mortgage calculator opens with a $375,000 home, 20% down and a 6.5% example rate over 30 years. The engine gives:
| Monthly payment | $2,396.20 |
|---|---|
| Principal and interest | $1,896.20 |
| Property tax per month | $375.00 |
Over 30 years at 6.5% you'll pay $682,637 on the loan, of which $382,637 is interest. Taxes, insurance and fees add $500.00 a month.
Sources
- Consumer Financial Protection Bureau, Regulation Z, Appendix H, Loan Estimate sample H-24(B). Read on .
- Consumer Financial Protection Bureau, Regulation Z, Appendix J, annual percentage rate computations. Read on .
- Consumer Financial Protection Bureau, Regulation DD, Appendix A, annual percentage yield calculation. Read on .
Educational tools
These calculators are educational tools, not financial advice and not offers of credit. A lender decides what it lends and at what rate; check every number with yours before you sign.