How to Calculate Savings Interest and Compound Growth

Saving money is a fundamental step toward achieving financial stability and realizing your future goals. To make the most of your savings, it is important to understand how banks calculate interest on your deposit accounts, and how you can leverage compound growth to build wealth faster.

1. Simple vs. Compound Interest

How interest is calculated fundamentally shapes your savings trajectory over time:

• Simple Interest: Interest is calculated solely on your initial deposit (the principal). It is common in short-term loans or simple certificate deposits.
• Compound Interest: The interest earned at the end of a period is added to the principal balance, and future interest is calculated on this new, larger balance. This cycle repeats, accelerating your growth.

The standard compound interest formula is:

Future Value = Principal × (1 + r)^n

Where r is the annual interest rate and n is the number of compounding years.

2. The Power of Recurring Deposits

While compounding is highly effective on a lump sum, it becomes incredibly powerful when combined with regular monthly contributions. By consistently adding to your savings, you feed the principal balance, which exponentially increases the base upon which interest compounds.

The Timing Effect:

Adding money at the start of compounding periods ensures that every single dollar spends the maximum amount of time earning interest.

To run simulations on your savings accounts, compare interest compounding frequencies (daily, monthly, or annually), and project your balance with regular savings plans, try our free Savings Interest Calculator.