What information do I need to calculate a loan payment?

Three inputs: the loan amount (principal), the annual interest rate, and the loan term (number of months or years). With these, you can calculate the fixed monthly payment using the standard amortization formula. Optional additional factors include origination fees (which increase effective cost), whether interest is fixed or variable, and whether payments are monthly, biweekly, or another frequency.

How does a longer loan term affect total cost?

A longer term lowers your monthly payment but significantly increases total interest paid. A $25,000 loan at 7% costs $497/month over 5 years (total interest: $4,830) versus $290/month over 10 years (total interest: $9,835). The 10-year loan costs over twice as much in interest despite the same rate. Choose the shortest term you can comfortably afford to minimize total borrowing costs.

What is amortization in loan payments?

Amortization is the process of spreading loan repayment over fixed periodic payments that each cover both interest and principal. Early payments are mostly interest (because the balance is high), while later payments are mostly principal. On a 30-year mortgage, the first payment might be 80% interest and 20% principal, gradually shifting until the final payments are almost entirely principal. An amortization schedule shows this breakdown for every payment.

Should I make extra principal payments on my loan?

Extra principal payments reduce your outstanding balance faster, which decreases total interest paid and can shorten your loan term. Even small additional amounts make a meaningful difference — adding $100/month to a $200,000, 30-year mortgage at 7% saves over $80,000 in interest and pays off the loan nearly 7 years early. Check that your loan has no prepayment penalty first, and verify extra payments are applied to principal, not just advanced toward future payments.

How is the monthly payment for a simple loan calculated?

The monthly payment (M) for a simple installment loan is calculated using the amortization formula: M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1], where P is the principal loan amount, i is the monthly interest rate (annual rate divided by 12), and n is the total number of payments (loan term in years multiplied by 12). For instance, a $20,000 loan at 6% annual interest over 3 years (36 payments) would use a monthly rate of 0.06/12 = 0.005. This formula ensures each payment consistently covers the accruing interest for that period and reduces the principal balance, leading to full repayment by the loan's end.

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Simple Loan 计算器

贷款和抵押贷款计算器

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贷款金额

年利率

贷款期限

年

额外还款

可选月额外还款

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仅供参考。此工具不构成财务建议。在做出投资或财务决策之前，请咨询合格的财务顾问。

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Reviewed August 2026

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Simple Loan 计算器

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