Calculate Compound Interest on Savings Account

Compound interest is the interest calculated on the initial principal and also on the accumulated interest of previous periods. This means your money grows exponentially over time, which can significantly increase your savings. Use our calculator to determine how much your savings will grow with compound interest over a specific period.

What is Compound Interest?

Compound interest is the addition of interest to the principal sum of a loan or deposit, or in other words, interest on interest. It's the result of reinvesting interest, either annually or more frequently, which means that you not only earn more interest on the original principal amount, but also on the accumulated interest of previous periods.

The key difference between simple interest and compound interest is that with simple interest, you only earn interest on the original principal amount. With compound interest, you earn interest on both the original principal and the accumulated interest from previous periods.

Compound interest is one of the most powerful tools for growing wealth over time. It's why many financial experts recommend saving and investing for the long term.

How to Calculate Compound Interest

Calculating compound interest involves several key variables: the principal amount (P), the annual interest rate (r), the number of times interest is compounded per year (n), and the time the money is invested for (t). Here's a step-by-step guide:

Determine the principal amount (P) - the initial amount of money you're investing.
Identify the annual interest rate (r) - the percentage rate at which your money grows.
Decide how often the interest is compounded (n) - typically annually, semi-annually, quarterly, or monthly.
Determine the time period (t) - the number of years the money will be invested.
Use the compound interest formula to calculate the future value of your investment.

Once you have these values, you can plug them into the compound interest formula to determine how much your money will grow over time.

The Compound Interest Formula

The standard formula for calculating compound interest is:

A = P(1 + r/n)^nt

Where:

A = the future value of the investment/loan, including interest
P = the principal investment amount
r = the annual interest rate (decimal)
n = the number of times that interest is compounded per year
t = the time the money is invested for, in years

This formula calculates the future value of an investment with compound interest. The more frequently interest is compounded, the more your money will grow over time.

Worked Example

Let's look at an example to illustrate how compound interest works. Suppose you invest $1,000 at an annual interest rate of 5%, compounded annually for 10 years.

Using the compound interest formula:

A = 1000(1 + 0.05/1)^1*10 = 1000(1.05)¹⁰ ≈ $1,628.89

After 10 years, your initial $1,000 investment would grow to approximately $1,628.89 with compound interest. This demonstrates the power of compound interest over time.

Frequently Asked Questions

What is the difference between simple and compound interest?

Simple interest is calculated only on the original principal amount, while compound interest is calculated on the original principal and also on the accumulated interest of previous periods. This means compound interest grows exponentially over time.

How often should interest be compounded?

The more frequently interest is compounded, the more your money will grow over time. However, the difference between compounding annually, semi-annually, quarterly, or monthly becomes smaller as the compounding frequency increases.

What factors affect compound interest?

The principal amount, interest rate, compounding frequency, and investment time all affect the amount of compound interest earned. Higher principal amounts, higher interest rates, more frequent compounding, and longer investment periods will all result in greater compound interest.

Is compound interest taxable?

The taxability of compound interest depends on the type of account and the jurisdiction. In many countries, interest earned on tax-deferred accounts like IRAs or 401(k)s is not taxed until withdrawal. However, interest earned on taxable accounts is typically taxed annually.

How can I maximize compound interest?

To maximize compound interest, consider investing in high-yield savings accounts, certificates of deposit, or other investment vehicles that offer competitive interest rates. Additionally, try to invest for the long term to take advantage of compounding over time.