Hydraulics & Pneumatics

For design and manufacturing engineers involved in buying or specifying fluid power components and systems.

CNC Machining Design Guide

Optimize your designs, reduce machining time, and lower your costs.

Autonomous Vehicle Engineering

The No. 1 media source for those developing the next generation mobility solutions.

Offshore

International news and technology for marine/offshore operations around the world.

more free magazines
Scenario 1: Find the Amount of Payment

Loan Amount (C)

Interest Rate % (R)

Compound Frequency (m)

No. of Payments (N)

Payment Frequency (q)

Payment Amount (P): 
Interest rate R% is always a yearly figure. However, in most loan situations it is compounded monthly. In this calculator the Payment Amount P is calculated by the following formula
where r is the adjusted equivalent interest rate
For most loans, interests are compounded monthly and payments are also made monthly (m=q=12). r is then simplified to R/1200:
Note that the number 100 is to convert the percentage value R% to decimal.
Scenario 2: Find the Interest Rate

Loan Amount (C)

Payment Amount (P)

No. of Payments (N)

Payment Frequency (q)

Compound Frequency (m)

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:
The annual interest rate R% is
Scenario 3: Find the Number of Payments

Loan Amount (C)

Interest Rate % (R)

Compound Frequency (m)

Payment Amount (P)

Payment Frequency (q)

No. of Payments (N): 
This calculator figures out the Number of Payments N by the following closed-form expression:
Notice that N has to be an integer, so the Payment Amount P might be slightly adjusted to satisfy this condition.