What does the Amortization Calculator do?
It converts the entered loan assumptions into payment, interest, total cost, and schedule-style outputs using deterministic formulas.
Finance Calculator
Amortization Calculator
Generate a detailed amortization schedule with opening balance, interest, principal, extra payments, closing balance, annual summary, and CSV export.
Last reviewed: June 21, 2026Amortization method set v1.0.0Finance method set v1.0.0: fixed-payment, amortization, payoff, comparison, flat-rate, and simple-interest formulas
What the Amortization Calculator does
The Amortization Calculator is the schedule-focused Finance tool for opening balance, interest, principal, extra payments, closing balance, and cumulative totals.
How to use the Amortization Calculator
Enter the values that describe the loan or interest scenario, then review the result, schedule, warnings, and assumptions before using the number.
- Enter principal, rate, term, frequency, and optional date.
- Add extra payments if relevant.
- Review schedule, annual summary, and CSV.
Formula
Interest = opening balance x periodic rate. Principal = scheduled payment - interest. Closing balance = opening balance - principal - extra principal.
Variables
The calculator uses the following variables in its formula layer.
- Opening balance
- Scheduled payment
- Interest
- Principal
- Extra principal
- Closing balance
Assumptions
These assumptions keep the calculation deterministic and transparent.
- Fixed rate.
- Periodic accrual.
- Final payment is adjusted to zero out balance.
Calculation steps
NexaCalc applies the formula in a fixed sequence so the output can be tested and repeated.
- Calculate scheduled payment.
- Generate each row.
- Cap final principal to avoid negative balance.
- Aggregate annual totals.
Worked examples
A 200,000 loan at 6% for 360 months has payment about 1,199.10.
First interest is 1,000 and first principal is about 199.10.
Total modeled interest is about 231,676.38 with no extra payments.
Result interpretation
The schedule shows how early payments are interest-heavy and later payments shift toward principal.
Limitations
The result is a model, not a lender quote or official disclosure.
- No mortgage taxes or insurance.
- No daily accrual.
- Large schedules are displayed with a capped preview and CSV export.
Frequently asked questions
Is the interest rate the same as APR?
No. The entered rate is used for the modeled interest calculation. APR may include other costs and lender disclosure rules.
Why can my lender's numbers differ?
Lenders can use different accrual conventions, rounding, fee timing, payment posting rules, taxes, insurance, and legal disclosures.
Does changing currency convert the amount?
No. Currency changes formatting only. NexaCalc does not fetch exchange rates or convert values.
Can I use this for approval decisions?
No. The calculator does not estimate eligibility, creditworthiness, approval probability, or suitability.
Are extra payments guaranteed to save interest?
The model applies extra payments to principal, but actual savings depend on lender prepayment terms and posting rules.
Does the schedule use daily accrual?
No. The amortization schedule uses periodic interest based on the selected frequency unless the page explicitly uses simple-interest day counts.
Is this financial advice?
No. It is a general education calculator and should be checked against lender disclosures and qualified advice when decisions matter.
References
Financial disclaimer
This calculator is for general educational use only. It is not financial, legal, tax, lending, or investment advice. Lender disclosures, compounding conventions, fees, taxes, insurance, prepayment rules, and local regulations can change actual loan costs.