Amortization
Calculator
Calculate loan payments, full amortization schedules, and interest savings from extra payments, for mortgages, auto loans, personal loans, and more.
| # | Date | Payment | Principal | Interest | Extra | Balance |
|---|
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Amortization Calculator: Loan Payment & Schedule Tool
Every borrower deserves to understand exactly where their money goes each month. With an amortization calculator, you can see the full breakdown of every payment: how much reduces your principal, how much goes to interest, and when you’ll make your last payment. This free tool calculates monthly payments for any fixed-rate loan, generates a complete amortization schedule, models extra payment savings, and shows you your payoff date, all in real time.
Quick formula: Monthly Payment (EMI) = P × r × (1+r)ⁿ ÷ [(1+r)ⁿ − 1] where P = loan principal, r = monthly interest rate (annual rate ÷ 12), n = total number of payments. This is the standard fixed-rate amortization formula used by banks and mortgage lenders worldwide.
How the Amortization Calculator Formula Works
This calculator measures the fixed monthly payment that pays off a loan over a set term, then breaks that payment down month by month into its principal and interest portions. It computes the payment amount once using the formula above, then simulates the loan balance shrinking one payment at a time to build the full schedule.
| Result | Formula | Notes |
|---|---|---|
| Monthly payment (EMI) | P × r × (1+r)ⁿ ÷ [(1+r)ⁿ − 1] | Fixed for the life of the loan |
| Interest this month | Current balance × r | Recalculated every month on the falling balance |
| Principal this month | Payment − Interest this month | Grows every month as interest shrinks |
| New balance | Previous balance − Principal this month | Any extra payment also reduces this directly |
P is your loan principal. r is your annual interest rate divided by 12, converted to a decimal. n is the total number of monthly payments across your loan term. Extra payments, when entered, reduce the balance beyond the required principal portion in that same month, which is why they shrink both future interest and the total payoff time.
Step-by-step calculation walkthrough
Step 1: Identify the inputs. Loan amount: $30,000. Annual interest rate: 7%. Loan term: 5 years (60 months).
Step 2: Apply the formula. Monthly rate = 7% ÷ 12 = 0.5833%. EMI = 30,000 × 0.005833 × (1.005833)^60 ÷ [(1.005833)^60 − 1].
Step 3: Perform the calculation. This works out to a monthly payment of $594.04. In month 1: Interest = 30,000 × 0.005833 = $175.00. Principal = 594.04 − 175.00 = $419.04. The new balance becomes 30,000 − 419.04 = $29,580.96, and the same process repeats every month with interest recalculated on this smaller balance.
Step 4: Interpret the result. A $30,000 loan at 7% over 5 years costs $594.04 a month. Unlike a large, long-term mortgage where interest dominates the early payments, this smaller, shorter loan already has principal ($419.04) outweighing interest ($175.00) in month 1, since a shorter term and smaller balance both work in the borrower’s favour. Over the full 5 years, the interest-versus-principal split keeps shifting further toward principal every month, exactly the pattern shown in the results chart above.
📐 The principal-vs-interest bar, the annual chart, and the full amortization table shown in your results all read from this same month-by-month simulation. Extra payments run through an identical loop with one added step: any extra amount is subtracted from the balance in the same month, directly ahead of the next month’s interest calculation, which is exactly why extra payments save more in interest than their face value.
Assumptions and limitations: the calculation is exact given a fixed interest rate for the full term, but it assumes the rate never changes, which rules out adjustable-rate loans unless you recalculate at each rate reset. It also only models principal and interest, real mortgage payments often bundle in property tax, homeowner’s insurance, and PMI, which this calculator doesn’t include. Bi-weekly payment frequency is modelled as an equivalent extra monthly amount rather than a literal bi-weekly payment schedule, a reasonable approximation that produces very close results to an actual bi-weekly plan.
How Loan Amortization Works
Amortization is the process of paying off a loan through regular, equal payments over time. The Consumer Financial Protection Bureau explains that each payment has two components: interest (the cost of borrowing) and principal (the actual debt repayment). In the early months of a loan, the vast majority of each payment covers interest. As the balance decreases, the interest portion shrinks and more of each payment goes toward principal, even though the payment amount stays the same throughout.
This front-loading of interest is why extra payments are so powerful early in a loan. Every dollar of principal you pay down early eliminates multiple dollars of future interest.
Understanding Principal and Interest
Principal
Principal is the original amount borrowed. Each monthly payment reduces the principal by a small amount. As the balance falls, less interest accrues each month, meaning more of your fixed payment goes toward principal, accelerating repayment over time.
Interest
Interest is calculated as the outstanding balance multiplied by the monthly rate. On a $350,000 mortgage at 6.5%, the first month’s interest is $350,000 × 0.5417% = $1,896. As the balance falls, this amount decreases month by month.
Extra payments
Extra payments reduce principal immediately, which reduces future interest charges. Even $100–200 extra per month on a 30-year mortgage can save tens of thousands in interest and shorten the loan by several years.
Bi-weekly payments
Switching from monthly to bi-weekly payments results in 26 half-payments per year, equivalent to 13 monthly payments instead of 12. This one extra payment per year can cut years off a 30-year mortgage with no change to your budget.
Amortization Schedule Example
| Month | Payment | Principal | Interest | Balance |
|---|---|---|---|---|
| 1 | $2,212 | $316 | $1,896 | $349,684 |
| 6 | $2,212 | $325 | $1,887 | $348,076 |
| 12 | $2,212 | $336 | $1,876 | $346,088 |
| 60 | $2,212 | $435 | $1,777 | $327,638 |
| 120 | $2,212 | $602 | $1,610 | $296,716 |
| 180 | $2,212 | $832 | $1,380 | $253,957 |
| 360 | $2,212 | $2,200 | $12 | $0 |
This example uses a $350,000 mortgage at 6.5% over 30 years. Notice how in month 1, only $316 of the $2,212 payment reduces the principal. By month 180 (year 15), principal repayment has grown to $832, more than 2.5 times the starting amount. By the final payment, almost the entire amount goes to principal.
3 Real-Life Examples
Three different loan situations, calculated the way the tool above does it.
| Situation | Inputs | Result | What it means |
|---|---|---|---|
| Financing a first car | $18,000 loan, 8.5% annual rate, 4-year term, no extra payments. | Monthly payment: $444. Total interest: $3,296. | Over the 4-year term, interest adds about 18% on top of the amount borrowed, a useful number to compare against a dealer’s advertised “low monthly payment” that might stretch the term out further. |
| Paying down a mortgage faster with extra payments | $420,000 loan, 6.75% annual rate, 30-year term, comparing no extra payment against $300/month extra. | Base interest: $560,680. With $300/month extra: $399,314 interest, payoff in 271 months (about 22.6 years) instead of 360. | An extra $300 a month saves approximately $161,000 in interest and cuts the loan short by roughly 7.4 years, a concrete number to weigh against other uses for that same $300. |
| Comparing a 30-year term to a 15-year term | $250,000 loan, 6% annual rate, comparing 30-year and 15-year terms. | 30-year: $1,499/month, $289,595 total interest. 15-year: $2,110/month, $129,736 total interest. | The 15-year term costs about $611 more per month but saves roughly $159,900 in interest overall, the classic trade-off between lower monthly payments and lower total cost. |
These are illustrative calculations using the same amortization formula the calculator above applies. They’re a planning tool, not a substitute for an actual loan offer from a lender.
Important Notes
- These are simulated projections, not a loan offer. The amortization math is exact given a fixed rate and term, but actual loan terms, fees, and approval depend on your lender and credit profile.
- Rounding. Displayed currency figures round to the nearest whole unit, or abbreviate to M or B for large values.
- This calculator only models principal and interest. Real mortgage payments often include property tax, homeowner’s insurance, and PMI (private mortgage insurance), none of which are included in the monthly payment shown here.
- Bi-weekly payments are modelled as an equivalent extra monthly amount. This produces results very close to, but not always identical to, a literal bi-weekly payment schedule with a lender.
- Adjustable-rate loans aren’t directly supported. The calculator assumes one fixed rate for the entire term; for an ARM, recalculate with the new rate at each reset period.
- Extra payments reduce the balance in the same month they’re made. This is why they save more in interest than their face value, each dollar of extra principal paid early eliminates interest on that dollar for every remaining month of the loan.
- Data privacy. All calculations run in your browser. Your inputs aren’t sent to a server, and the PDF and CSV exports are generated locally on your device.
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