Loan Calculator
Free loan calculator: compute monthly payments, total interest, and a full amortization schedule. Supports Brazilian Price & SAC systems. No signup.
Updated May 2026
Amortization system
Market Context
Values are educational estimates. Consult a financial institution.
Total interest
R$541.50
+68.4% Principal
First payment
R$3.69
CALCULATED FOR MONTH 1
Total cost
R$791.50
Sum of 360 installments
| MONTH | PAYMENT | INTEREST | AMORTIZATION | BALANCE |
|---|---|---|---|---|
| 1 | R$3.69 | R$3.00 | R$0.69 | R$249.31 |
| 2 | R$3.69 | R$2.99 | R$0.69 | R$248.61 |
| 3 | R$3.68 | R$2.98 | R$0.69 | R$247.92 |
| ... showing 4 of 360 months ... | ||||
| 360 | R$0.70 | R$0.01 | R$0.69 | R$0.00 |
How to Use This Loan Calculator
Enter your numbers, pick a system, get a full amortization schedule
1. Enter amount, rate, and term
Loan amount, interest rate (monthly or annual), and the number of months you'll be paying.
2. Pick your market and system
US, Europe, or Brazil — each with realistic default rates. Switch to Brazil to compare Price, SAC, and SAM side by side.
3. Read the results and export
Total interest, first payment, and total cost at a glance — then download the full month-by-month schedule as a CSV.
What This Loan Calculator Does
A full amortization schedule, not just a single payment number
Complete amortization schedule
Every month, broken down into payment, interest, principal paid, and remaining balance — not just a final total.
Fixed and declining payment systems
Standard fixed-payment amortization (the system used for most mortgages, auto, and personal loans) plus Brazil's SAC and SAM systems for comparison.
Three markets, real reference rates
Switch between US, Europe, and Brazil to auto-fill realistic loan amounts, rates, and terms for each market, including live Brazilian Central Bank data.
Monthly or annual rate input
Enter the rate the way your loan document states it — the calculator converts annual rates to the monthly rate used in the math automatically.
CSV export
Download the entire schedule to open in Excel or Google Sheets for further analysis.
Example: $300,000 at 6.5% annual, 360 months
When You'll Use This
The most common scenarios among people who use this calculator
Mortgage shopping
Model a 15- or 30-year mortgage and see exactly how much of each payment goes to interest versus principal in the early years.
Auto loan payments
Enter the amount after your down payment and check whether the monthly payment actually fits your budget.
Comparing loan offers
Run two lenders' rate and term quotes side by side to see the real dollar difference, not just the headline rate.
Planning extra payments
Shorten the term in the simulator to see how much interest a lump-sum or extra monthly payment would actually save you.
Common Mistakes
Assuming the lowest monthly payment is the cheapest loan
A lower payment usually means a longer term or a declining-balance system deferred — it doesn't mean less interest paid overall. Always check the total cost, not just the first payment.
Comparing the nominal rate instead of the APR
The nominal interest rate ignores fees, insurance, and closing costs. The APR (or CET in Brazil) reflects the real cost of the loan — that's the number to compare across lenders.
Entering an annual rate as if it were monthly
US and European loan documents usually quote an annual rate; Brazilian mortgages usually quote a monthly rate. Mixing the two produces a payment that's off by a large margin.
Why Use This Loan Calculator
Most free loan calculators online show you one number — the monthly payment — and stop there. This one builds the entire amortization schedule, so you can see exactly how the balance, interest, and principal shift every single month of the loan.
It also supports three markets with realistic defaults and, for Brazil, live reference rates pulled from the Central Bank, plus a genuine side-by-side comparison between fixed-payment and declining-payment amortization systems. No signup, no email wall — the whole schedule is yours to export as a CSV.
Fixed Payment vs. Equal-Principal Amortization
The two most common ways loans are structured
Frequently Asked Questions
For a standard fixed-payment loan: PMT = PV × [i×(1+i)^n] / [(1+i)^n − 1], where PV is the loan amount, i is the monthly interest rate, and n is the number of payments. For an equal-principal (SAC) loan, the principal portion stays constant (PV ÷ n) while interest is calculated on the remaining balance, so the payment starts higher and declines every month.
Resources
Official explainer from the US Consumer Financial Protection Bureau on how lenders arrive at a monthly principal and interest payment.
Plain-language definitions of amortization, APR, principal, and other terms used throughout a loan estimate.
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