Dollar-Cost Averaging Calculator: Average Cost & Lump Sum

DCA means investing a fixed amount at regular intervals regardless of the current price. When prices rise you automatically buy fewer units; when prices fall you buy more. Over time this produces an average cost per unit that tends to be lower than if you had bought everything at a single price peak. It is not a guarantee of profit but a discipline that removes the pressure to time the market. Many investors apply DCA automatically through payroll-deducted retirement contributions, so the strategy runs without any manual timing decisions each month. In this calculator's long-term example, investing $500 a month at a 7 percent assumed annual return grows to $253,768 after 20 years, with $133,768 of that total coming from compounding rather than direct deposits. The same $500 monthly plan extended to 30 years reaches $584,726, showing how the compounding share keeps growing the longer the schedule runs.

Historical data shows lump-sum outperforms DCA in roughly two thirds of 12-month periods because markets trend upward over time. A $10,000 lump sum at 7% for 10 years reaches $19,671.51, while the same $10,000 spread over 12 months ends at $19,074.47, because each monthly part waits 5.5 months on average before it is invested. DCA tends to win in flat or falling markets and is the right default when you are investing regular income rather than a windfall. Over a shorter three-year window the dollar gap is smaller: at a fixed 7%, the same $10,000 grows to $12,250.43 at once and to $11,878.62 when phased in over 12 months, $371.81 behind. This comparison assumes no transaction costs; adding a $2 per-trade fee to 12 monthly purchases costs DCA an extra $24 that a single lump-sum purchase never pays, a small but real drag when contribution frequency is high.

Volatility is an ally for DCA investors. When prices swing down you buy more units at lower prices, reducing your average cost. When prices swing up you buy fewer units but your existing holdings gain value. A sequence of down months followed by recovery can produce a better outcome than if prices had simply risen steadily, because the cheaper purchases compound at the recovered price.

Divide the total amount you invested by the total number of units you bought. Each purchase buys its amount divided by the price, so you first work out the units per purchase, add them up and then divide. In the 4-month example on this page, $500 a month at prices of $50, $55, $48 and $52 buys 39.12 units for $2,000, an average cost of $2,000 / 39.12 = $51.12. The plain average of those four prices is $51.25, so the plan bought slightly below the average price, because the fixed $500 bought more units in the two months with a price under that average. The same formula works for averaging down: 100 shares at $50 and 100 shares at $40 cost $9,000 for 200 shares, or $45 a share. The Average cost tab does this sum for up to 12 purchases and lists the units bought with each one, so you can check the cost basis of your own position.

It works for what it is designed to do, but not as a way to beat the market. DCA guarantees one thing: with the same amount every time, your average cost per unit is never higher than the average of the prices you paid, because a fixed amount buys more units when the price is low. It also removes the decision of when to invest, which helps many people keep buying through downturns. What it does not do is earn more than investing at once. A 2012 Vanguard study of US, UK and Australian markets found that a lump sum beat a 12-month DCA plan in about two thirds of historical periods, because markets rose more often than they fell. In this calculator's DCA vs lump sum tab, $10,000 at 7% for 10 years ends at $19,671.51 when invested at once and at $19,074.47 when spread over 12 months. For a regular salary, DCA is simply how you invest, so the comparison only matters when you hold a large amount today.

The calculator supports seven frequencies: Daily=365, Weekly=52, Biweekly=26, Semimonthly=24, Monthly=12, Quarterly=4, Annually=1. All are normalized to a monthly timeline internally: each one is spread evenly over the months and added at month end. So $1,200 a year and $100 a month give exactly the same result, and a higher frequency does not add extra averaging points or compounding cycles in the calculation. What frequency does change is the transaction cost if there is a per-trade fee. Monthly is practical for most investors as it aligns with income cycles and keeps transaction fees manageable. Weekly contributions mean 52 purchases a year instead of 12, which multiplies a flat per-trade fee by roughly four times over the same period. Someone paid every two weeks often matches contributions to each paycheck using the Biweekly=26 setting, rather than forcing a monthly schedule that doesn't line up with actual cash flow. If your broker charges no transaction cost at all, frequency becomes a cash-flow question rather than a cost trade-off, and weekly contributions then carry no downside beyond the extra setup effort.

A 0.2% TER on $200 per month at 7% return over 30 years leaves $224,883. Raising the TER to 0.5% leaves $212,142, close to what a 6.5% return without fees would give. That 0.3 percentage point difference costs $12,740 over 30 years. Choosing a low-cost fund is one of the highest-impact decisions a long-term DCA investor can make. Over a shorter 10-year horizon the same 0.3 percentage point gap only costs $551, since fees have less time to compound against a smaller balance. Many index funds now charge a TER between 0.03% and 0.10%, well below the 0.2% used in this example, so checking your actual fund's TER before running the numbers often shows the real drag is smaller than the illustration suggests. A TER above 1% on an actively managed fund, by contrast, can erase far more than $12,740 from the same 30-year outcome.

Broad global equity index funds have returned roughly 7 to 10 percent annually before inflation over the long term. A common conservative planning assumption is 5 to 7 percent, which leaves room for fees, taxes, and below-average periods. To model real (inflation-adjusted) growth, subtract expected inflation (typically 2 to 3 percent) from the nominal return before entering it. Test a range of values rather than relying on a single number. A more optimistic assumption turns the same $500 monthly plan into $319,426 after 20 years at 9 percent and $359,130 at 10 percent, instead of the $253,768 produced at 7 percent: a swing of $65,658 to $105,362 from the return assumption alone. Bond-heavy portfolios typically return 3 to 5 percent, so a mixed 60/40 allocation of stocks and bonds often lands closer to 5 or 6 percent than to the higher equity-only figure. Running the calculator once at a conservative rate and once at an optimistic rate gives a realistic range rather than a single number that could mislead your planning.

Transaction costs are deducted from each contribution before it is invested. A $2 fee on a $100 contribution removes 2 percent of that deposit. At weekly frequency that is $104 per year in fees; at monthly it is $24. At daily frequency with a $1 fee you would pay $365 per year in fees alone. For small contribution amounts, a flat per-trade fee can significantly erode returns at high frequencies.

This option raises your recurring contribution at the start of each year, either by a fixed amount or by a percentage. Starting with $200 per month and a fixed increase of $20 means year 2 uses $220, year 3 uses $240, and so on, for $7,920 of contributions over three years. A 5 percent increase instead gives $200, $210 and $220.50, or $7,566 over the same three years. The fixed amount suits a plan that grows by the same step every year, while the percentage keeps your contribution in line with a salary that rises with inflation. Even a small annual raise makes a meaningful difference over 20 to 30 years because the higher contributions also compound over the remaining horizon.

This calculator models transaction costs and TER but not income or capital gains taxes. In a taxable account, taxes may be due on dividends or realised gains. In a tax-advantaged account such as an ISA, 401k, or pension, growth is sheltered. A practical workaround is to reduce the assumed annual return by 0.5 to 1 percent to get a rough after-tax estimate for a taxable account.

Nominal return is the raw percentage your investment grows each year before accounting for inflation. Real return is what remains after inflation erodes purchasing power. At 7% nominal return and 3% inflation, the real return is roughly 4%. This calculator outputs nominal values. To think in real terms, enter a return already reduced by your inflation assumption, or divide the final balance by (1 + inflation rate)^years.

DCA can be applied to stocks, index funds, ETFs, bonds, cryptocurrencies, gold, and other assets that can be purchased in recurring amounts. The price-averaging benefit is largest in volatile asset classes where prices swing widely. For stable or steadily rising assets, lump-sum investing may outperform. This calculator models any asset with a fixed assumed return and does not adjust for asset-specific volatility patterns.

Nominal means values are shown in future currency units without adjusting for reduced purchasing power caused by inflation. A balance of $253,768 in 20 years will buy less than $253,768 buys today if inflation averages 3 percent per year. To convert to today's purchasing power, divide by (1.03)^20, which gives roughly $140,500. Subtracting 2 to 3 percent from your return assumption before entering it is a simpler way to get approximate real values.

No. This Dollar-Cost Averaging Calculator is for informational and planning purposes only and does not constitute financial, tax, legal or investment advice. Actual results depend on market conditions, fees, taxes, and other factors the calculator does not capture. Always consult a qualified financial adviser for decisions involving real money.