engineering fundamentals Finance: Loan Calculator
Directory | Career | News | Standards | Industrial | SpecSearch®
Home Membership Magazines Forum Search Member Calculators

Materials

Design

Processes

Units

Formulas

Math
LoanIQ for iPhone is now available.
efunda's iPhone version of its online loan, lease, and APR calculators. Choose any variable (loan amount, payment, interest rate, etc.) as the unknown and calculate the result in real-time as other variables are entered. App Store
Scenario 1: Find the Monthly Payment

Loan Amount (C)

Interest Rate % (R)

Number of Months (N)

Monthly Payment (P): 
Interest rate R% is always a yearly figure. However, in most loan situations it is compounded monthly. In this calculator the monthly payment is calculated by the following formula where r = R/1200:
Scenario 2: Find the Interest Rate

Loan Amount (C)

Monthly Payment (P)

Number of Months (N)

Interest Rate % (R): 
For given C, P and N, one can only solve the following equation for r by numerical means.
Given the rather smooth behavior of this equation, this calculator employs the Newton-Raphson method with an educated initial guess:
Scenario 3: Find the Number of Payments

Loan Amount (C)

Interest Rate % (R)

Monthly Payment (P)

Number of Months (N): 
This calculator figures out the number of months N by the following closed-form expression:
Notice that N has to be an integer, so the monthly payment P might be slightly adjusted to satisfy this condition.
Home  Membership  About Us  Privacy  Disclaimer  Contact  Advertise

Copyright © 2014 eFunda, Inc.