Monthly Interest Calculator on Savings Account

Calculate monthly interest on your savings account with this simple online tool. Understand how interest compounds over time and how to maximize your savings with different interest rates and deposit amounts.

How to Use This Calculator

Using our monthly interest calculator is straightforward. Follow these steps to get accurate results:

Enter the principal amount (initial deposit) in the first field.
Input the annual interest rate (APR) in the second field.
Select the compounding frequency (monthly is most common for savings accounts).
Enter the number of years you plan to keep the money in the account.
Click the "Calculate" button to see your results.

The calculator will display the total amount in your account after the specified period, the total interest earned, and a growth chart showing your savings over time.

Formula Explained

The calculation uses the compound interest formula:

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

For monthly compounding (n=12), the formula simplifies to:

A = P × (1 + r/12)^(12t)

The calculator then calculates the total interest earned by subtracting the principal from the final amount.

Worked Example

Let's calculate the future value of $1,000 invested at 3% annual interest rate for 5 years with monthly compounding:

A = 1000 × (1 + 0.03/12)^(12×5) A = 1000 × (1.0025)^60 A ≈ 1000 × 1.1606 A ≈ $1,160.60 Total interest earned = $1,160.60 - $1,000 = $160.60

Using our calculator, you can see how different amounts, interest rates, and time periods affect your savings.

APY vs APR

Many savings accounts advertise an Annual Percentage Yield (APY), which is the real rate of return considering compounding. The relationship between APY and APR is:

APY = (1 + APR/n)^n - 1 For monthly compounding: APY = (1 + APR/12)^12 - 1

For example, a 3% APR with monthly compounding results in approximately a 3.04% APY. Our calculator uses APR but shows the equivalent APY for comparison.

Frequently Asked Questions

How often is interest calculated on savings accounts?: Most savings accounts calculate interest monthly, which means your balance grows slightly each month based on the daily average balance.
Is the interest I earn taxable?: Interest earned on savings accounts is generally taxable as ordinary income in the year it's earned, unless you have a tax-advantaged account like an IRA.
Can I withdraw money from my savings account without penalty?: Most savings accounts allow unlimited withdrawals without penalty, but check your specific account terms as some may have restrictions.
How does compounding affect my savings?: Compounding means your interest earns interest, which significantly increases your savings over time. Monthly compounding is more frequent than annual compounding, leading to slightly higher returns.
What's the difference between a savings account and a money market account?: Savings accounts typically offer higher interest rates but may have withdrawal limits, while money market accounts often have check-writing privileges and no withdrawal limits, but may have lower interest rates.