Compound Interest on Savings Account Calculator

Compound interest is the magic behind growing your savings over time. Unlike simple interest that only calculates on the original principal, compound interest earns interest on both the original amount and the accumulated interest from previous periods. This powerful financial tool can help your money grow significantly faster than simple interest accounts.

How Compound Interest Works

Compound interest is calculated on the initial principal and also on the accumulated interest of previous periods. This means your money works harder over time, creating exponential growth rather than linear growth seen in simple interest accounts.

Key Concepts

Principal (P): The initial amount of money you deposit
Interest Rate (r): The annual interest rate (expressed as a decimal)
Compounding Frequency (n): How often interest is compounded per year (annually, semi-annually, quarterly, monthly)
Time (t): The time the money is invested for, in years

How Compounding Frequency Affects Growth

The more frequently interest is compounded, the faster your money grows. For example, monthly compounding will yield more interest than annual compounding with the same annual rate.

Compound interest is one of the most powerful financial tools available. It's the reason why saving regularly can lead to significant wealth over time, even with modest interest rates.

Using the Calculator

Our compound interest calculator makes it easy to estimate how much your savings will grow over time. Simply enter your principal amount, annual interest rate, compounding frequency, and investment period, then click "Calculate".

Input Fields

Principal Amount: The initial deposit you're making
Annual Interest Rate: The percentage rate your money will earn annually
Compounding Frequency: How often interest is calculated and added to your account
Investment Period: How many years you plan to keep the money invested

Result Interpretation

The calculator will show you the future value of your investment, the total interest earned, and a growth chart showing how your money grows over time.

The Formula

The formula for compound interest is:

A = P × (1 + r/n)^nt
Where:
A = Amount of money accumulated after n years, including interest.
P = Principal amount (the initial amount of money)
r = Annual interest rate (decimal)
n = Number of times that interest is compounded per year
t = Time the money is invested for, in years

This formula calculates the future value of your investment by applying the interest rate to both the principal and the accumulated interest over each compounding period.

Worked Examples

Example 1: Annual Compounding

If you invest $1,000 at an annual interest rate of 5% compounded annually for 10 years:

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

After 10 years, you would have approximately $1,628.89, earning $628.89 in interest.

Example 2: Monthly Compounding

With the same principal and interest rate but compounded monthly:

A = 1000 × (1 + 0.05/12)^12×10 ≈ 1000 × (1.004167)¹²⁰ ≈ $1,647.01

Monthly compounding yields approximately $1,647.01, or $47.01 more than annual compounding for the same investment.

Frequently Asked Questions

How does compound interest differ from simple interest?

Compound interest earns interest on both the original principal and the accumulated interest from previous periods, while simple interest only calculates on the original principal.

How often should interest be compounded for maximum growth?

The more frequently interest is compounded, the faster your money grows. Monthly compounding typically provides the best balance between convenience and growth.

Is compound interest taxable?

In most countries, interest earned on savings accounts is taxable as ordinary income. Check with your tax advisor for specific rules in your jurisdiction.

How does inflation affect compound interest?

Inflation can erode the purchasing power of your money over time. To maintain real value, your investment should grow faster than inflation.