Investment Calculator
Project the future value of an investment with regular contributions, periodic compounding, and an expected rate of return.
Inputs
Future value
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Total deposited
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Investment growth
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Final monthly income (4% safe withdrawal)
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Time to double (rule of 72)
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About Investment Calculator
Realistic rate of return
Long-term US stock market: ~10% nominal, ~7% real after inflation. Balanced 60/40 stock/bond: 5-7% real. Use conservative numbers — 5-7% real for diversified portfolios is reasonable for planning.
Time vs amount
Starting early matters far more than amount. $500/mo for 30 years at 7% becomes ~$610k. $1000/mo for 15 years at 7% becomes only ~$317k. Same total contribution, half the time.
Tax-advantaged accounts
Use 401(k), IRA, Roth IRA, HSA to shelter growth from taxes. Each has limits and rules — but the long-term tax savings often exceed any direct return advantage.