Investment & Savings Calculator
See how your money grows with compound interest, plan savings goals and project retirement balances.
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Compound interest is the engine of long-term wealth building. These calculators help you see how investments grow over time, figure out how much to save each month to reach a goal, calculate return on investment and project your retirement balance. All calculations use standard financial formulas and run entirely in your browser.
Frequently asked questions
At 7% annual return with monthly compounding and no additional contributions, $10,000 grows to about $40,387. Add $200/month in contributions and it reaches approximately $144,720.
Divide 72 by your annual return rate to estimate doubling time. At 7%, money doubles in about 10.3 years. At 10%, about 7.2 years. It is a quick mental math shortcut for investment planning.
A common rule is 25x your annual expenses (the 4% rule). If you spend $50,000/year, aim for $1,250,000. The retirement calculator projects your balance based on current savings and contributions.
7% after inflation is the historical S&P 500 average. Use 4-5% for savings accounts and 5-6% for conservative portfolios. Be realistic rather than optimistic.
Use annualized return (from the ROI calculator). It converts any holding period to a yearly rate so you can compare a 2-year investment to a 5-year one on equal terms.
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