Why Compound Interest Matters

Compound interest means you earn interest not just on what you put in, but also on the interest you've already earned. Over time, that "interest on interest" grows your money faster than simple interest would.

Illustration: $200/month at 5% for 10 years grows to roughly $31,350, of which about $7,350 is interest earned on top of the $24,000 you deposited. That $7,350 is "free money" from compounding.

What Your Money Can Grow To

Here's how different monthly deposits grow at a 5% annual rate over 10 years (starting from $0):

Monthly Deposit	You Contribute	Future Value	Interest Earned
$100	$12,000	~$15,675	~$3,675
$200	$24,000	~$31,350	~$7,350
$500	$60,000	~$78,375	~$18,375
$1,000	$120,000	~$156,750	~$36,750

The higher your rate and the longer you save, the bigger the compounding effect. Even small regular deposits add up dramatically over decades.

Tips for Building Savings

Start early: Time is the most powerful factor in compounding.
Automate deposits: Set up automatic transfers so saving happens without thinking.
Build an emergency fund first: Most advisors suggest 3–6 months of expenses in an accessible account before investing for the long term.
Increase deposits with raises: Put part of any raise into savings.
Keep fees low: High fees eat into your returns over time.

Frequently Asked Questions

What's the difference between simple and compound interest?

Simple interest is paid only on the principal. Compound interest is paid on the principal plus previously earned interest, so it grows faster over time.

How often does this calculator compound?

It compounds monthly, which is common for many savings accounts. Some accounts compound daily; the difference is usually small.

Is a higher interest rate always better?

Generally yes, but also consider fees, minimum balances, and whether the rate is fixed or variable. A slightly lower rate with no fees can sometimes beat a higher rate with heavy fees.

Is this financial advice?

No. This is a general estimation tool. For decisions about saving, investing, or retirement, consult a qualified financial professional.

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