Compound Interest Calculator (USA)

Use our Compound Interest Calculator to estimate the future value of your investments with compounding. Calculate total returns based on principal, rate, time, and compounding frequency!

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Understanding Compound Interest in US

Standard Formula: A = P × (1 + r/n)nt

Continuous Compounding: A = Pert

Where:

  • A = Future amount
  • P = Principal amount
  • r = Annual interest rate (decimal)
  • n = Compounding periods per year
  • t = Time in years
  • e = Euler's number (~2.71828)

Daily Compounding: n = 365

Monthly Compounding: n = 12

Quarterly Compounding: n = 4

Taxable Accounts: Subject to capital gains and dividend taxes

Traditional IRA: Tax-deferred growth, taxed on withdrawal

Roth IRA: After-tax contributions, tax-free growth

401(k): Employer-sponsored, often with matching

CDs: Fixed term, fixed rate, FDIC insured

Brokerage Accounts: Flexible investing, taxable events

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Compound Interest Examples
Principal Rate 5 Years 10 Years
$10,000 5% $12,763 $16,289
$50,000 7% $70,128 $98,358
$10K + $500/mo 8% $48,834 $108,623
$100,000 10% $161,051 $259,374
Calculations assume monthly compounding. Returns are illustrative.
Current US Rates
Account Type Rate Range Compounding
High-Yield Savings 3-5% Daily
1-Year CD 4-5.5% Daily
5-Year CD 3.5-4.5% Daily
S&P 500 Index 10% (historical) Continuous
Money Market 4-5% Daily
Maximizing Returns
  • 1. Maximize 401(k) employer matching
  • 2. Use Roth IRA for tax-free growth
  • 3. Choose higher compounding frequencies
  • 4. Reinvest dividends automatically
  • 5. Consider index funds for low-cost investing