Loan Calculator — Free Online Loan & Mortgage Calculator
Calculate monthly payments, total interest, and view amortization schedules for any loan or mortgage. All calculations happen locally — nothing leaves your browser.
How is a monthly loan payment calculated? A fixed-rate loan uses the amortization formula M = P × r(1 + r)^n ÷ ((1 + r)^n − 1), where P is the amount borrowed, r is the annual rate divided by 12, and n is the number of monthly payments. Borrowing $250,000 at 6% over 30 years gives r = 0.005, n = 360 and a payment of $1,498.88, of which $1,250 is interest in month one.
How to Use the Loan Calculator
- Enter the amount you are borrowing — Use the principal, not the purchase price. For a home that means the price minus your deposit; for a car it means the price minus any trade-in and deposit. Fees rolled into the loan belong in this figure too.
- Enter the annual interest rate — The field takes an annual percentage and divides it by 12 internally, so type 6 for a 6% loan rather than 0.5. It accepts steps of 0.125 to match the eighths lenders usually quote, up to a maximum of 30%.
- Pick a term — The four pills cover 10, 15, 20 and 30 years; the Term (years) box below them takes anything from 1 to 50 for car loans, personal loans and long mortgages alike. Both controls drive the same value.
- Try an extra monthly payment — Adding an amount here raises the headline monthly payment and shows the balance falling faster in the schedule. Note that the Total Interest, Total Cost and Payoff Date cards always describe the scheduled loan, so they do not drop when you add an overpayment.
- Find the real payoff month in the schedule — Scroll the amortization table to the first row where Balance reaches $0.00 — that month is your true payoff point when overpaying. Rows after it are padding for the original term and show no interest and no principal.
- Copy the summary — Copy Summary puts the principal, rate, term, monthly payment, total interest and total cost on your clipboard as plain text, ready to paste next to a quote from another lender. The summary uses the scheduled payment and excludes any extra.
How the Payment Formula Works
A fixed-rate loan is an annuity: one constant payment, repeated, that has to cancel the debt exactly on the last month. The payment that does this comes from a single closed-form expression, and it is the same arithmetic behind a mortgage, a car loan and a personal loan.
M = P × r(1 + r)ⁿ ÷ ((1 + r)ⁿ − 1)P is the principal, r is the monthly rate (the annual rate ÷ 100 ÷ 12) and n is the total number of monthly payments. For $250,000 at 6% over 30 years, r is 0.005 and n is 360, which gives $1,498.88 a month. A zero-rate loan takes a separate branch — with no interest the payment is simply the principal divided by the number of months, because the general formula divides by zero at r = 0.
Why early payments are almost all interest
The payment is constant but its composition is not. Each month the lender charges interest on whatever is still outstanding, and the rest of your payment reduces the balance:
Interest this month = remaining balance × rIn month one of that 30-year example, $250,000 × 0.005 is $1,250 of interest, leaving only $248.88 of principal — under 17% of the payment. The crossover, where principal finally exceeds interest within a single payment, does not arrive until around month 221, more than eighteen years in. Only in the closing years does almost the whole payment go to the balance. This is why total interest on a long loan looks so large next to the amount borrowed: $289,595 of interest on $250,000 of principal at 6% over 30 years.
What the extra payment does — and does not — change
An extra payment is applied straight to the balance after the scheduled interest and principal, so it shrinks the amount the next month's interest is charged on and compounds from there. In the amortization table you can watch the balance fall faster and hit zero early. The four stat cards, however, always describe the loan as originally scheduled: Total Interest, Total Cost and Payoff Date are computed from the contract payment and the full term, and only the large headline figure adds your extra to the monthly amount. To see what an overpayment is really worth, compare the month number where the balance first reaches zero against the full term.
The Payoff Date card counts the term forward from today rather than from the Start Date field, so it is a rough month-and-year marker rather than a contractual date. The Start Date is kept with the shareable link so a scenario reloads the way you left it.
What the Term Costs You
Term is the input people underestimate. A shorter term raises the monthly payment but cuts total interest sharply, because the balance spends far less time accruing. These figures are all $250,000 borrowed at 6%.
| Term | Monthly payment | Total interest | Total repaid |
|---|---|---|---|
| 10 years | $2,775.51 | $83,062 | $333,062 |
| 15 years | $2,109.64 | $129,736 | $379,736 |
| 20 years | $1,791.08 | $179,859 | $429,859 |
| 30 years | $1,498.88 | $289,595 | $539,595 |
Moving from 30 years to 15 costs an extra $611 a month and saves nearly $160,000 in interest. That is the trade the term pill is really making, and it is worth seeing before the monthly payment becomes the only number in the conversation.
How sensitive the payment is to the rate
| Rate | Monthly payment | Total interest | Extra interest vs 4% |
|---|---|---|---|
| 4% | $1,193.54 | $179,674 | — |
| 5% | $1,342.05 | $233,139 | +$53,465 |
| 6% | $1,498.88 | $289,595 | +$109,921 |
| 7% | $1,663.26 | $348,772 | +$169,098 |
| 8% | $1,834.41 | $410,388 | +$230,714 |
On a 30-year loan of $250,000, each additional percentage point adds roughly $150 to $170 a month and between $53,000 and $62,000 of interest over the term. That is the scale of what shopping around, or an eighth of a point on a rate sheet, is actually worth.
What Overpaying Achieves
Because interest is charged on the outstanding balance, money paid early is worth far more than money paid late. The table below takes the same $250,000 at 6% over 30 years and adds a fixed monthly overpayment.
| Extra per month | Total monthly | Loan cleared in | Total interest | Interest saved |
|---|---|---|---|---|
| $0 | $1,498.88 | 30 years | $289,595 | — |
| $100 | $1,598.88 | 25 years 6 months | $238,023 | $51,572 |
| $200 | $1,698.88 | 22 years 3 months | $203,363 | $86,232 |
| $500 | $1,998.88 | 16 years 5 months | $143,467 | $146,128 |
An extra $100 a month — 6.7% more than the scheduled payment — removes four and a half years and over $51,000 of interest. The returns taper as the overpayment grows, because each additional dollar is fighting a smaller and smaller remaining balance, but they never turn negative. Before committing, check your agreement for early repayment charges, which are common on fixed-rate mortgages, and confirm the lender applies overpayments to the principal rather than holding them against future instalments.
Interest Rate, APR and What This Tool Leaves Out
The interest rate is the price of borrowing the principal. The APR bundles that rate together with the fees required to get the loan — origination fees, discount points, broker fees and, on some mortgages, insurance — expressed as a single annual percentage. Because those costs are spread over the term, APR is the better figure for comparing two offers with different fee structures, while the note rate is what actually generates the interest line on your statement.
Enter the note rate if you want the payment your lender will bill, and the APR if you want a closer estimate of the true annual cost. The two diverge most on short loans, where the same fixed fees are amortized over fewer months.
Several real costs sit outside this calculator entirely. A mortgage payment usually also carries property tax, buildings insurance and, below a certain equity level, mortgage insurance — often collected together in escrow and easily adding 20-30% to what leaves your account. Variable and tracker rates move with a reference rate, so a single fixed figure only describes the current period. Balloon payments, interest-only periods, offset accounts and payment holidays all break the constant-payment assumption. And nothing here models tax relief on interest, which exists in some countries and not others.
This calculator is informational and produces estimates from the figures you enter. It excludes taxes, insurance, fees and early repayment charges, and it is not financial advice. Your lender's official illustration is the authoritative document — use this to compare scenarios, and speak to a qualified adviser or mortgage broker before committing to a loan.
Frequently Asked Questions
Use the amortization formula M = P × r(1 + r)ⁿ ÷ ((1 + r)ⁿ − 1), where P is the amount borrowed, r is the annual rate divided by 12 and n is the number of monthly payments. A $250,000 loan at 6% over 30 years gives r = 0.005, n = 360 and M = $1,498.88. The calculator above runs the same expression, so entering those three values reproduces the figure exactly.
Every extra dollar comes straight off the balance, so next month's interest is charged on a smaller amount and the effect compounds. On $250,000 at 6% over 30 years, an extra $100 a month clears the loan in 25 years 6 months instead of 30 and saves about $51,500 of interest. Check your agreement for early repayment charges first, and confirm the lender applies overpayments to the principal rather than to future instalments.
Because the four stat cards describe the loan as originally scheduled. Total Interest, Total Cost and Payoff Date are all computed from the contract payment over the full term, and only the large headline figure adds your extra to the monthly amount. The amortization table is where the overpayment shows up: scroll to the first row where Balance reads $0.00 and that month number is the real payoff point.
The interest rate is the price of borrowing the principal and is what generates the interest line on your statement. The APR bundles that rate with the fees needed to obtain the loan — origination fees, discount points, broker fees — into one annual percentage, which makes it the fairer basis for comparing two offers with different fee structures. Enter the note rate for the payment your lender will bill, or the APR for a closer estimate of true annual cost.
On $250,000 at 6%, the 15-year payment is $2,109.64 against $1,498.88 for 30 years — $611 a month more — but total interest falls from $289,595 to $129,736. If the higher payment fits comfortably, the shorter term is far cheaper. If it is tight, take the 30-year term and overpay voluntarily: you keep the flexibility to stop in a bad month, at the cost of a slightly higher rate on most mortgage rate sheets.
No. The formula, the schedule and the chart all run in JavaScript in your browser, and nothing is uploaded or stored on a server. Your inputs are written into the page URL so a scenario can be bookmarked or shared, which means that link carries the amount, rate, term, start date and any extra payment. Treat it as private before pasting it into a message or a document.
No. It calculates principal and interest only. A real mortgage payment usually also carries property tax, buildings insurance and, below a certain equity level, mortgage insurance, often collected together in escrow — together they can add 20-30% to what leaves your account each month. Use the Mortgage Calculator when you need the full housing payment rather than the loan portion alone.
The table always prints one row per month of the original term. When an extra payment clears the loan early, the rows after that point show the scheduled payment with zero principal, zero interest and a zero balance — they are padding, not payments you owe. Read the first $0.00 balance as the end of the loan and ignore everything below it.
Yes. Any fixed-rate loan repaid in equal monthly instalments uses the same formula, so a five-year car loan and a thirty-year mortgage differ only in the numbers. Set the term box to the number of years — it accepts 1 to 50 — and enter the annual rate. It is not suitable for interest-only periods, balloon payments, credit cards with a percentage-based minimum, or income-contingent student loan repayment plans.
Use Cases
Checking a Lender's Quote
Enter the amount, rate and term from an offer and confirm the monthly payment matches what the lender has written down. A discrepancy usually means fees are rolled in, the rate is the APR rather than the note rate, or the term is not what you assumed.
Working Backwards From an Affordable Payment
You know what you can pay each month, not what you can borrow. Adjust the loan amount until the payment lands on your figure, then use that principal plus your deposit as the top of your realistic price range before you start viewing.
Pricing a Car Loan Against a Cash Purchase
Set the term to three or five years and read the total repaid. Comparing that against the sticker price shows the finance cost as one number, which is the figure a dealer's monthly-payment framing tends to obscure.
Deciding Whether to Overpay or Invest
Read the interest saved by an extra $200 a month, then compare it against what the same $200 might earn elsewhere. Overpaying is a guaranteed return equal to your loan rate, which is a fair benchmark for any alternative.
Finding Out How Much Equity You Will Have
Scroll the amortization table to a specific month to see the outstanding balance on the date you might move or remortgage. Principal minus that balance is the equity the loan has built by then, before any change in the property's value.
Teaching How Amortization Behaves
Show a class why month one of a 30-year loan is 83% interest and the crossover does not arrive for eighteen years. Changing the term pill and watching the interest slice of the donut chart move makes the point faster than an explanation does.