Free Online Loan & Mortgage Calculator

What the loan and mortgage calculator shows

This loan and mortgage calculator works out the monthly payments on a loan, as equal annuity payments or with equal principal, at a fixed rate or with one rate change after a set number of years. It then shows what the loan costs in total and how every payment splits between interest and principal. It works the same way for a home mortgage, a car loan, a personal loan or any other amortizing loan: enter the amount you borrow, or the price and your down payment, the annual interest rate and the term, and it does the rest.

The questions it answers are the ones most borrowers ask before signing: how much will I pay each month, how much interest will I pay over the life of the loan, how fast does the balance actually go down, and what changes if the rate or the term is different. The amortization schedule answers the last question month by month, and a yearly chart shows the same picture at a glance.

The calculator runs entirely in your browser. Nothing you enter is sent anywhere.

In this guide:

• How to fill in each field and read the headline, the figures, the chart and the payment schedule
• The exact formulas the calculator uses, and what it leaves out
• How amortization works, and the difference between annuity and differentiated repayment
• How the term, the rate, rate resets and extra payments change the total interest
• A payment lookup table, three worked examples in US dollars and common mistakes

Borrowing is compound interest working against you instead of for you. If that idea is new, the basics article on compound interest and the time value of money explains it from the start.

How to use the loan and mortgage calculator

The calculator opens in US dollars with a $320,000 annuity loan at 15% over 20 years. The examples in this guide keep USD. The UAH / USD / EUR switch sits in the header of the Your numbers panel on wide screens and under More options on phones and tablets. It only changes the symbol in the results; there is no conversion.

The main inputs, from top to bottom:

1. Start from. Loan amount or Purchase price. With Loan amount you enter the Loan principal, the amount you borrow. With Purchase price you enter the price and a Down payment, as an amount or a percentage of the price, and the calculator subtracts it for you; a line under the field shows both, such as "= $80,000 · 20% of the price" for a $400,000 home. Switching between the two keeps the loan amount.
2. Annual interest rate. The nominal yearly rate on the loan, in percent. Use the interest rate from the offer, not the APR. The slider runs to 40%, and you can type up to 100%.
3. Loan term. Years or months. The slider starts at 1, but in years you can type down to 1/12, which is one month.
4. Repayment. Annuity keeps every payment the same. Equal principal repays the same slice of the loan each month, so the payments fall over time.

More options holds three more settings:

• Term unit. Months or years. It changes only how the term is shown, never the loan: 30 months shows as 2.5 years. The calculator counts the term in whole months.
• The rate changes during the term. Opens Years until the change and New rate; the new rate starts out equal to the current one. With 5 years, the new rate applies from month 61.
• One-time fees & insurance. Upfront costs you pay once, such as an origination fee, appraisal or closing costs. They are added to the total cost but not included in the monthly payment.

Values typed outside a range are pulled back to its limit. On phones, the money fields and the down payment use − and + buttons instead of a slider: amounts move in steps of 5,000 in USD or EUR and 100,000 in UAH, and a down payment entered as a percentage moves by 1 percentage point; the rate and the term keep their sliders.

Reading the results

On wide screens the results stay in view to the right of the inputs. The headline is the Monthly payment; when the payments vary, because of equal principal or a rate change, it becomes the First payment. A bar under it splits the principal from the total interest. The figures follow. Principal is the amount borrowed. Total interest paid is the payments minus the principal; fees are not counted as interest. Total amount paid is all the monthly payments plus the one-time fees. Interest share is the total interest divided by the sum of the monthly payments, again without fees. When the payments vary, Last payment is added, and with Purchase price the Down payment is shown too. If the down payment covers the whole price, a note says no loan is needed.

The Chart tab has one stacked bar per year of the loan: the lower, light navy part is principal repaid that year and the upper, amber part is interest. The Payment schedule tab lists every month with the columns Month, Payment, Principal, Interest and Balance. All amounts are shown in whole currency units.

Pin to compare keeps the current inputs as a reference. The headline then shows the change in the payment, such as +$773 vs pinned in Example 1 below, the chart adds the pinned loan's yearly payments as a dashed line, and a Pinned scenario caption lists its principal, rate, term, repayment and payment. Switching the currency, Reset or a reload clears it. PDF exports the inputs, the results and every row of the schedule, without the pinned scenario. Share shares a link to the page without your numbers, and Reset restores the defaults, including US dollars. On phones and tablets, the results sit in a bar fixed to the bottom of the screen; Details opens the figures, the tabs and the buttons.

How the loan payment is calculated

By default the calculator uses the annuity method, the standard way fixed-rate mortgages and most consumer loans are repaid: one payment amount for the whole term, large enough to cover each month's interest and bring the balance to exactly zero at the end. The other method, equal principal, is compared further down.

The annuity formula

r = annual rate ÷ 12
n = term in months
M = P × r × (1 + r)^n ÷ ((1 + r)^n − 1)

• P is the loan principal
• r is the monthly interest rate as a decimal (6.5% a year is 0.065 ÷ 12, about 0.005417)
• n is the number of monthly payments (30 years is 360)
• M is the monthly payment

For $300,000 at 6.5% over 30 years, M is $1,896. If the rate is 0%, the formula would divide by zero, so the calculator uses M = P ÷ n instead: $12,000 over 12 months at 0% is exactly $1,000 a month.

Building the amortization schedule

With either method, interest is charged each month on the balance left after the previous payment, and the rest of the payment reduces the balance. For an annuity:

Interest in month k = balance after month k−1 × r
Principal in month k = M − interest in month k
Balance after month k = balance after month k−1 − principal in month k

In month 1 of the $300,000 example, interest is $300,000 × 0.065 ÷ 12 = $1,625, so $271 of the $1,896 repays principal and the balance falls to $299,729. Month 2 charges interest on that slightly smaller balance, and so on until month 360, which leaves a balance of zero.

Totals and the interest share

Total of payments = sum of all monthly payments
Total interest = total of payments − P
Total amount paid = total of payments + one-time fees
Interest share = total interest ÷ total of payments

For an annuity with no rate change, the total of payments is M × n. For the $300,000 example: $682,633 in payments, of which $382,633 is interest, an interest share of 56.1%.

Assumptions behind the numbers

• A fixed rate, or one rate change. After a change, an annuity payment is recalculated on the remaining balance over the remaining term, so the term stays the same; with equal principal only the interest changes. Some contracts keep the payment and change the term instead, so your contract decides.
• Monthly payments, each due one month apart, with interest at the annual rate divided by 12. There are no biweekly or weekly payment options.
• Annuity or equal principal. Annuity payments stay equal until the rate changes; with equal principal, the balance falls by P ÷ n every month.
• No extra payments, missed payments, grace periods or balloon payments. The loan runs for exactly the term you enter.
• No rounding to cents. Real lenders round the payment, and the final payment often differs by a few cents; the calculator keeps full precision and displays whole units.
• Fees are paid in cash and do not affect the payment, the interest or the interest share. There is no APR calculation.
• Not modelled: property taxes, homeowner's or mortgage insurance, escrow, prepayment penalties, inflation and exchange rates. Results are estimates, not a loan offer.

Amortization schedule explained

An amortization schedule shows why the early years of a long loan feel slow. Here is the $300,000 loan at 6.5% over 30 years, with selected rows from the calculator's schedule:

The payment never changes, but its make-up does. After five years you have paid $94,605 in interest and reduced the balance by only $19,167. After ten years the balance is still $254,328. Principal overtakes interest in month 233, after more than 19 years, and half the original balance is gone only in month 257.

Two practical points follow. First, the balance you would owe if you sold the home or refinanced after a few years is much higher than a straight-line guess suggests; read it from the Balance column. Second, any extra principal paid early removes balance that would otherwise be charged interest for decades, which is why early prepayments save the most. The rule behind both is the time value of money, explained in the compound interest basics article.

Annuity vs differentiated payments

There are two common ways to repay a loan in monthly instalments. The calculator does both: pick one with the Repayment switch.

• Annuity payments are equal every month. The interest part shrinks and the principal part grows, as in the table above. Most US fixed-rate mortgages and car loans work this way.
• Differentiated payments, also called declining, straight-line or equal-principal repayment, repay the same amount of principal every month. Interest is added on the remaining balance, so the first payment is the largest and each later payment is smaller. Some lenders, particularly in parts of Europe and Ukraine, offer this as the "classic" schedule.

Principal part = P ÷ n
Payment in month k = P ÷ n + balance after month k−1 × r
Total interest at a fixed rate = r × P × (n + 1) ÷ 2

The table compares both on $300,000 at 6.5% over 30 years. Every figure comes from the calculator: the left column with Repayment set to Annuity, the right one with Equal principal.

The differentiated schedule saves $89,321 of interest, because principal is repaid faster and less balance is left to charge interest on. The cost is a first payment $562 higher: pin the annuity run and switch the schedule, and the headline shows +$562 vs pinned. Its payment drops below the annuity payment only in month 126, after more than 10 years. Over a 5-year car loan the gap is far smaller: on $28,000 at 7.5% the annuity costs $5,664 in interest and the differentiated schedule $5,337.

Which suits you depends on cash flow rather than on arithmetic alone. The annuity keeps the required payment lower and steady. The differentiated schedule is cheaper if you can afford the high early payments. With an annuity loan that allows penalty-free prepayments, paying extra in the early years moves you toward the lower-interest path without committing to the higher payment.

How the loan term changes total interest

A longer term lowers the monthly payment and raises the total interest. The table uses $300,000 at 6.5% for each term:

Going from 15 to 30 years lowers the payment by $717 a month and more than doubles the interest, from $170,398 to $382,633. The extra 15 years cost $212,235. The trade-off is flexibility: the 30-year payment is easier to carry if your income drops or an emergency comes up. In practice, lenders often price shorter terms at lower rates, which widens the gap further; enter the rates you are actually offered for each term.

Whichever term you pick, the monthly payment has to fit next to your other costs and savings. A loan payment that leaves no room for an emergency fund turns any surprise expense into new debt.

How the interest rate changes the payment

At a fixed principal and term, each rate step raises the payment by more than the step before. The table uses $300,000 over 30 years:

The rates are illustrative, not a forecast or a quote. Between 5% and 8%, each half-point adds $93 to $104 to the monthly payment on this loan, and $33,445 to $37,314 of interest over 30 years. The difference between 6% and 7% alone is $197 a month and $71,012 in total.

Fixed vs variable rate

Unless you add a rate change, the calculator assumes a fixed rate. With a variable or adjustable rate, the payment is recalculated when the rate changes, based on the balance at that point and the remaining term. The calculator can model one such reset. Suppose the $300,000 loan at 6.5% resets after five years: under More options, tick The rate changes during the term, enter 5 years and the new rate. The calculator recalculates the payment on the $280,833 balance left after month 60 over the remaining 25 years, and Last payment shows the new amount.

A two-point rise adds $365 a month for the remaining 25 years. Real adjustable loans have their own reset dates, caps and index rules, and many reset more than once, so use your loan documents for the exact mechanics and the calculator to size the risk.

Paying off a loan early with extra payments

The calculator does not take extra payments as an input, but it can still answer the most common prepayment question: how much extra per month would pay the loan off by a given year? Enter the same principal and rate with the shorter term. Paying that payment on your current loan retires it in exactly that many years, because the arithmetic is the same.

This is the answer to "how to cut 10 years off a 30-year mortgage": on $300,000 at 6.5%, about $341 a month of extra principal from the start does it, and saves $145,821 of interest. Starting later saves less, because the expensive early years are already behind you.

A lump-sum prepayment can work in two ways, depending on the lender. If the term stays the same and the payment is recalculated, called a recast, run the lower balance over the remaining term: paying $20,000 off the $280,833 balance after five years lowers the payment from $1,896 to $1,761. If the payment stays the same, the loan ends sooner instead, which usually saves more interest.

Before prepaying, check two things. Ask the lender how extra payments are applied, so they reduce principal rather than being held for future payments. And check for a prepayment penalty: the US Consumer Financial Protection Bureau describes it as a fee that some lenders charge if you pay off all or part of your mortgage early, and notes it typically applies to paying off the whole balance rather than small extra amounts. Whether paying down a low-rate loan beats investing the same money is a separate question; risk and return explains why a guaranteed saving at the loan rate is not the same as an uncertain investment return.

Interest rate, APR and what the payment leaves out

Three numbers are easy to mix up when you compare loan offers.

• Interest rate. The yearly cost of borrowing the money. It sets the monthly payment, and it is what the calculator needs.
• APR. The CFPB explains that the APR reflects the interest rate, any points, mortgage broker fees, and other charges that you pay to get the loan, so it is usually higher than the interest rate. It is useful for comparing lenders. Entering it as the interest rate overstates the payment.
• Total monthly housing cost. The CFPB describes principal, interest, taxes and insurance, known as PITI, as the basic elements of a monthly mortgage payment, with taxes and insurance often collected through escrow.

The calculator's Interest share also ignores fees. In Example 3 below, the fee adds a quarter to the interest cost of a small loan, which is why comparing total cost, not only the rate, matters. Over a long mortgage, also remember that a fixed payment becomes lighter in real terms if prices and incomes rise; inflation and why money loses value explains the mechanism.

Loan payments at a glance

This grid gives the monthly payment per $100,000 borrowed, computed with the calculator, for common rates and terms. Scale it to your loan: for $250,000, multiply the figure by 2.5.

Reading across a row shows how much a longer term lowers the payment; reading down a column shows the cost of a higher rate. At 7% over 30 years, each $100,000 costs $665 a month and $139,509 of interest over the full term.

Worked examples

Each example uses USD as the display currency and shows what the calculator returns for the inputs listed.

Common mistakes with loan and mortgage calculators

• Entering the home price instead of the loan amount. The principal is what you borrow. Subtract your down payment first, or choose Purchase price and let the calculator do it.
• Using the APR as the interest rate. The APR includes fees and is higher than the rate that sets the payment. Enter the interest rate, and put upfront costs in the fees field.
• Treating the payment as the full housing cost. Property taxes, homeowner's insurance, mortgage insurance and association dues are not included.
• Judging a loan by the monthly payment alone. A longer term always lowers the payment and always raises the total interest. Look at Total interest paid next to it.
• Assuming equity builds evenly. In the early years most of each payment is interest. Read the balance for the year you might sell or refinance from the schedule.
• Forgetting fees rolled into the loan. If the lender finances the fees, add them to the principal, because you pay interest on them.
• Ignoring rate resets. A low introductory rate on an adjustable loan says little about the payment after the reset. Tick The rate changes during the term and test a higher rate for the rest of the loan.

Limitations and next steps

This calculator answers the core questions about an amortizing loan, with annuity or equal-principal repayment, at a fixed rate or with one rate change: the payment, the total interest, the total cost including one-time fees, and how the balance falls month by month. It does not model more than one rate change, extra or missed payments, APR, taxes, insurance or prepayment penalties, and it does not know what you can afford or what a lender will approve.

Use it to size and compare loans, then look at the rest of your finances:

• The emergency fund calculator shows how much cash to keep before you take on a large monthly payment.
• The compound interest calculator shows the other side of interest, for example what investing the extra payment might grow to instead.
• The inflation impact calculator shows how a fixed payment and a remaining balance look in today's money.
• The investment goal calculator helps plan how much to save each month for a down payment.

For background, read about compound interest and the time value of money and why an emergency fund comes first. For a decision about your own mortgage or refinancing, compare official loan estimates from several lenders and consider a qualified, independent adviser who can look at your full situation.