Loansloth

Personal Loan Calculator

A personal loan calculator turns your loan amount, interest rate, and term into a fixed monthly payment. It also shows the total interest and total cost, so you can compare offers before you borrow.

By the Loansloth Editorial Team · Last updated 2026-09-16

Enter your numbers and press Calculate. Nothing you type leaves your browser.

Compare personal loan offers Run the numbers first

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How this calculator works

A personal loan is repaid in equal monthly installments. Each payment covers the interest owed for that month plus a slice of the principal, so the balance falls a little faster every month.

The calculator uses the standard amortization formula:

M = P * r * (1 + r)^n / ((1 + r)^n - 1)

Total interest is the monthly payment times the number of payments, minus the amount borrowed. When the rate is 0%, the payment is simply P / n.

The rate you enter is your own assumption. Lenders set rates based on credit history, loan amount, and term, so your actual offer may differ.

Frequently asked questions

How is the monthly payment calculated?
The calculator uses the standard amortization formula M = P * r * (1 + r)^n / ((1 + r)^n - 1), where r is the annual rate divided by 12 and then by 100, and n is the number of monthly payments. Each payment covers that month's interest plus a portion of the principal.
Why does a longer term cost more overall?
A longer term spreads the principal over more months, so each payment is smaller, but you pay interest for more months. Total interest equals the monthly payment times the number of payments, minus the amount borrowed.
What interest rate should I enter?
Use the rate from an offer you have received or a rate you want to test. Rates vary by lender, credit history, loan amount, and term, so treat the rate you enter as an assumption rather than a quote.
Does this calculator include fees?
No. This tool covers principal and interest only. Origination or other upfront fees are not included; the APR calculator shows how fees change the yearly cost of credit.

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