Tool: Loan calculator · Embed · All how-we-calculate pages · Questions
Purpose
Estimate a fixed monthly payment, total interest, and month-by-month schedule for a single installment loan under stated inputs. Educational only.
Core formulas
- Monthly rate
r = APR ÷ 100 ÷ 12 -
Base payment (r > 0):
P × r × (1+r)^n / ((1+r)^n − 1)where P is principal and n is months - If APR is 0: payment = principal ÷ n
- Each month: interest = balance × r; principal portion = payment − interest
- Optional extra monthly is added to the base payment before running the schedule
What we intentionally leave out
- Origination fees, prepayment penalties, insurance, and taxes
- Variable rates, deferred interest, and promotional teaser periods
- Credit scores, approval odds, and debt-to-income underwriting
- Multi-loan snowball/avalanche portfolios (use separate runs per loan)
Related
Last reviewed: August 9, 2026.
YMYL notice: This site is for education only. It is not financial, tax, or investment advice. Nestfigure is not a bank, credit union, broker, investment adviser, or fiduciary. Product terms, rates, and penalties vary—always read your institution’s disclosures before acting. Calculator results are mathematical estimates, not bank quotes.