Savings Calculator
Project your future balance, interest earned, and wealth growth with compound interest.
Calculation Examples
How to Use the Savings Calculator
Start by entering your initial deposit in the Principal field. Then enter the annual interest rate your bank pays. Select the Compounding Frequency, which sets how often earned interest is added to your balance (daily, monthly, quarterly, or annually).
For ongoing contributions, enter your monthly deposit and choose whether it lands at the beginning or end of each period. Click the calculate button to see your projected future value, total interest earned, and a split between your own deposits and compound growth. It suits an emergency fund, a down payment, or any long-term savings goal. Results are projections at a fixed rate, not guarantees and not financial advice.
How Savings Interest Calculations Work
Compound interest pays interest on earlier interest, while simple interest pays only on your original principal. The calculator uses the standard formula \(A = P(1 + r/n)^{nt}\), where \(A\) is the final balance, \(P\) is the principal, \(r\) is the annual rate as a decimal, \(n\) is the number of compounding periods per year, and \(t\) is the time in years. For regular deposits, it adds the future value of an annuity.
Worked example: $5,000 at 5% with $100 added at the end of each month, compounded monthly, grows to about $13,217 after 5 years. The principal grows to $6,417 and the deposits to $6,801. You deposit $11,000 in total, so interest is about $2,217. Compounding frequency changes the effective yield: 5% compounded annually yields 5.000%, monthly 5.116%, and daily 5.127%. On $10,000 over 10 years, daily compounding earns only about $17 more than monthly. For a quick estimate of doubling time, divide 72 by the rate in percent: at 4%, money doubles in about 18 years.
Useful Tips 💡
- Recheck your rate every quarter. Savings rates follow Federal Reserve policy, banks change them without notice, and some top rates are promotional and drop after a set period.
- Subtract inflation to see real growth. A 4.5% rate with 3% inflation gives a real return of about 1.5% (exactly 1.46%).
- Check deposit insurance. FDIC coverage is $250,000 per depositor, per bank, per ownership category, so split larger balances across banks or categories.
📋Steps to Calculate
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Enter your starting principal amount and current annual interest rate.
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Set the time period and select your compounding frequency (daily, monthly, quarterly, or annually).
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Click Calculate to see your projected balance, total interest, and contribution breakdown.
Mistakes to Avoid ⚠️
- Using simple interest instead of compound interest. At 5% for 20 years on $10,000, simple interest gives $20,000, while annual compounding gives $26,533.
- Selecting the wrong compounding frequency. At 5% for 20 years on $10,000, annual compounding gives $26,533 and monthly compounding gives $27,126, a difference of $593.
- Ignoring inflation. A nominal 5% rate with 3% inflation leaves a real return of only about 1.9%.
- Mixing up deposit timing. Beginning-of-period deposits earn one extra period of interest. On $100 a month at 5% for 5 years, that adds about $28 ($6,829 versus $6,801).
Practical Applications📊
Build an emergency fund: $400 a month for 12 months at 4% compounded monthly reaches about $4,889, which is $4,800 deposited plus about $89 in interest.
Compare accounts: $10,000 for 10 years at 4.5% compounded annually grows to about $15,530, but at the 0.38% national average rate (FDIC, August 2026) it grows to only about $10,387.
Plan long-term goals: $500 a month for 30 years at a constant 7% adds up to about $610,000 on $180,000 of deposits. Real returns vary from year to year, so treat this as a scenario.