Amortization Calculator

Generate a full year-by-year amortization schedule showing principal, interest, and remaining balance for any loan. Free, instant, no signup.

%
years
Formula: PMT = P × r / (1 − (1 + r)^−n)
  • P = loan principal
  • r = monthly interest rate
  • n = total months

How to use the Amortization Calculator

  1. Enter your values. Fill in the fields with your numbers.
  2. Calculate. Press Calculate to run the amortization calculator.
  3. Use the result. Copy the result or try a related tool next.

Why use our Amortization Calculator

Instant results. Enter your figures and the amortization calculator returns an answer in seconds.
Free & private. Runs in your browser — no signup, and nothing is sent to a server.
Accurate. Uses standard formulas so you can rely on the numbers.

Free to use — premium coming soon

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About the Amortization Calculator

The Amortization Calculator turns a single loan into a complete, payment-by-payment repayment plan. You enter the loan amount, the annual interest rate, and the term in years, and it builds the full amortization schedule: each scheduled payment is split into the part that covers interest and the part that reduces what you still owe. Unlike a basic payment calculator that just tells you the monthly figure, this tool shows how that figure is allocated every single month and how your remaining balance shrinks toward zero. It works for mortgages, car loans, student loans, and personal loans that are repaid in equal installments.

Use it whenever you want to understand the true cost of borrowing before or during a loan. It answers practical questions: how much total interest will I pay over the life of this loan, how long until I have paid off half the principal, and how would a shorter term or a lower rate change the numbers. Because early payments are heavily weighted toward interest, the schedule is especially useful for spotting how slowly the balance moves in the first years and for comparing a 15-year versus a 30-year term side by side. Many people run it before refinancing or accepting a loan offer.

Under the hood it uses the standard fixed-payment (annuity) formula: A = P * r(1+r)^n / ((1+r)^n - 1), where P is the principal, r is the periodic interest rate (annual rate divided by 12 for monthly payments), and n is the total number of payments. Once the level payment A is found, each month the calculator multiplies the current outstanding balance by r to get that month's interest, subtracts it from the payment to get the principal portion, and reduces the balance by that principal. Repeating this for every period produces the schedule, with interest falling and principal rising over time.

All calculations run entirely in your browser, so the loan figures you type are never uploaded to a server or stored anywhere. Results are mathematically accurate for a standard fully amortizing, fixed-rate loan with equal periodic payments. Real lenders may differ by a few cents due to rounding conventions, day-count methods, or fees, and the tool does not include property taxes, insurance, PMI, or variable-rate adjustments. Treat the output as a precise planning estimate for the principal-and-interest portion of your loan rather than an exact quote from your lender.

Frequently asked questions

What formula does this amortization calculator use?

It uses the standard amortizing-loan payment formula A = P * r(1+r)^n / ((1+r)^n - 1), where P is the loan amount, r is the interest rate per period (annual rate divided by 12 for monthly payments), and n is the total number of payments. Each month's interest is then the current balance times r, and the rest of the payment reduces the principal.

Why does so much of my early payment go to interest?

Interest each month is charged on the outstanding balance, which is highest at the start of the loan. As you pay down the principal, the interest portion shrinks and more of your fixed payment goes toward the balance, so the principal share grows steadily over the term.

How do extra payments change the schedule?

Any amount paid above the scheduled payment goes straight to principal, lowering the balance that future interest is calculated on. This shortens the loan term and can save a significant amount of total interest, since the savings compound across every remaining payment.

Is a 15-year loan better than a 30-year loan?

A 15-year term has higher monthly payments but amortizes faster and costs far less total interest. A 30-year term lowers the monthly payment but stretches out the balance, so you pay more interest overall. Run both in the calculator to compare the trade-off for your situation.

Does the result include taxes, insurance, or fees?

No. The schedule covers only principal and interest. Items like property taxes, homeowners or PMI insurance, HOA dues, and origination fees are not included, so your actual lender payment may be higher than the figure shown here.

From our blog

How the Army One-Site Tape Test Works and How to Estimate Your Score

By the Super Simple Digital Tools Team · Updated June 2026

The Army Body Composition Program exists to keep soldiers within a healthy body composition range, and in 2024 it moved to a simpler way of measuring it. Where the old method required taping multiple sites and applying log-based equations, the current one-site test asks for just your body weight and the circumference of your abdomen. That change makes the assessment faster, more consistent between graders, and easy to replicate at home, which is exactly what this calculator does.

The process starts with a screening, not a tape. Each soldier is first checked against a height and weight table for their age and sex. If you fall at or under the maximum screening weight for your height, you meet the standard and no tape test is needed. Only when you exceed that weight does the abdominal measurement come into play to determine your body fat percentage, so knowing your number in advance tells you whether the tape will ever come out.

Taking the measurement correctly matters more than people expect. Use a flexible tape that does not stretch, remove belts and bulky clothing, and stand tall with feet about hip-width apart. Place the tape at the level of your navel, keep it horizontal all the way around, and snug it against the skin without compressing the tissue. Read it at the end of a relaxed breath out. Because a single reading can be off, the Army takes three and averages them to the nearest half inch.

Once you have weight and abdomen in hand, the formula does the rest. Men and women use different equations because body fat distributes differently, but both depend only on those two inputs. Plug your averaged abdomen measurement and current weight into the calculator and it returns an estimated percentage. The tool then compares that figure to the maximum allowed for your age group, giving you a clear pass or work-needed signal rather than just a raw number.

Treat the output as a planning tool. Trends matter more than any one reading: track your estimate every couple of weeks as you train, and you will see how abdominal measurement responds to changes in diet and conditioning. When an official assessment is on the calendar, measure under the same conditions each time so your home estimates stay comparable, and remember that your unit's graded result is the one that counts on the record.

  • Average three abdomen readings to the nearest half inch, just as a grader would, instead of trusting a single measurement.
  • Measure at the navel at the end of a relaxed exhale, and never suck in or push your stomach out.
  • Compare your weight to the height and weight screening table first; if you are under it, the tape test may not apply at all.
  • Re-check your estimate at the same time of day and in similar conditions so progress between sessions is genuinely comparable.

Read the full guide →

Tool by the Super Simple Digital Tools Team. Reviewed by our editorial team. Free to use, no signup required.

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