Dollar Cost Averaging Calculator
Estimates the future value of a portfolio built through fixed monthly investments at a consistent rate of return. Use it to project long-term wealth accumulation when investing a set amount every month.
About this calculator
Dollar-cost averaging (DCA) means investing a fixed dollar amount at regular intervals regardless of price. The core future-value formula for regular contributions is: FV = monthlyInvestment × {[(1 + r)^n − 1] / r} × (1 + r), where r = (annualReturn / 100) / 12 is the monthly rate and n is the number of months. This calculator also applies a volatility adjustment factor (1 + volatility/100) to approximate the real-world dampening effect of price swings on compound growth — since arithmetic mean returns overstate actual compounded gains in volatile markets. The formula rewards consistency: small monthly amounts compounded over decades grow into substantial sums due to the exponential nature of compound interest.
How to use
Invest $300 per month for 120 months (10 years) at a 7% annual return with 15% volatility. Monthly rate r = 0.07 / 12 ≈ 0.005833. Base FV = 300 × [(1.005833^120 − 1) / 0.005833] × 1.005833 ≈ 300 × 173.08 ≈ $51,924. Volatility adjustment: $51,924 × (1 + 0.15) ≈ $59,713. You invested $36,000 in total, so the projected gain is roughly $23,713.
Frequently asked questions
How does dollar cost averaging reduce investment risk?
By investing a fixed amount regularly, you automatically buy more shares when prices are low and fewer when prices are high, lowering your average cost per share over time. This removes the pressure of trying to time the market perfectly. During downturns, your fixed contribution purchases more units, which amplifies gains when markets recover. It is especially powerful for long investment horizons of 10 years or more.
What is the difference between dollar cost averaging and lump-sum investing?
Lump-sum investing deploys all capital at once, which historically outperforms DCA in steadily rising markets because more money is invested earlier. DCA spreads purchases over time, reducing the impact of a poorly timed single entry. In volatile or declining markets DCA often produces a lower average cost basis. Most individual investors benefit from DCA simply because they receive income monthly rather than having a lump sum available upfront.
How does market volatility affect dollar cost averaging returns?
Higher volatility increases the spread between the high and low prices at which you buy, which can actually lower your average cost per share — a phenomenon called volatility harvesting. However, volatility also means the arithmetic average return overstates the true compounded (geometric) return. The calculator's volatility factor approximates this drag, giving a more realistic projection than a simple compound-interest formula would provide.