WiseIQ Editorial Team
Independent editorial — no lender writes our content · Updated March 2026
See how your savings grow over time with compound interest. Calculate the power of regular contributions and time in the market.
See how your savings grow over time with compound interest. Calculate the power of regular contributions and time in the market.
What is compound interest?
Compound interest is interest calculated on both your initial principal and the accumulated interest from previous periods. Unlike simple interest (calculated only on principal), compound interest grows exponentially over time — this is why Albert Einstein reportedly called it "the eighth wonder of the world."
How often should interest compound?
More frequent compounding means slightly more growth. Daily compounding earns marginally more than monthly, which earns more than annual. For most savings accounts, the difference between daily and monthly compounding is small. The interest rate matters far more than compounding frequency.
What is the Rule of 72?
The Rule of 72 is a quick way to estimate how long it takes to double your money. Divide 72 by your annual interest rate. At 6% interest, your money doubles in 72/6 = 12 years. At 8%, it doubles in 9 years. This rule works for any compounding investment.
Should I use a high-yield savings account or invest in the stock market?
High-yield savings accounts (4%–5% APY) are best for emergency funds and short-term goals (under 3 years) because they're FDIC-insured with no risk. For long-term goals (5+ years), investing in diversified index funds has historically returned 7%–10% annually, significantly outpacing savings accounts despite short-term volatility.
Recommended books to go deeper on this topic
Timeless lessons on wealth, greed, and happiness — the most important book on how to think about money.
View on Amazon →A 6-week program to set up your savings, investments, and spending so your money works on autopilot.
View on Amazon →As an Amazon Associate, WiseIQ earns from qualifying purchases. This does not affect our editorial recommendations.
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Last reviewed: April 2026 | How we rank products
Timeless lessons on wealth, greed, and happiness — the most important book on how to think about money.
View on Amazon →A 6-week program to set up your savings, investments, and spending so your money works on autopilot.
View on Amazon →As an Amazon Associate, WiseIQ earns from qualifying purchases. This does not affect our editorial recommendations.