How to Calculate DCA
What is DCA?
Dollar Cost Averaging (DCA) invests a fixed amount at regular intervals regardless of price, reducing timing risk by automatically buying more units when prices are low.
Formula
Total cost = Investment per period × Number of periods; Average cost per unit = Total cost / Total units acquired
- I
- Investment per period (Currency)
- n
- Number of periods (Integer)
- r
- Average annual return (Percentage)
Step-by-Step Guide
- 1Invest fixed amount each period
- 2Buy more units when price is low, fewer when high
- 3Average cost per unit tends below average price
- 4Best for volatile assets over long time horizons
Worked Examples
Input
$200/month for 20 years at 7% avg return
Result
Total invested $48k; Value ≈ $104k
Frequently Asked Questions
Does DCA guarantee lower cost than lump sum?
No. If markets rise consistently, lump sum wins. DCA shines in down or sideways markets. Over 50+ years, lump sum typically outperforms, but DCA reduces timing risk.
What's the best DCA interval?
Daily, weekly, monthly, or quarterly all reduce timing risk. Monthly is practical for most people. Shorter intervals reduce large market timing mistakes.
Should I DCA into index funds or individual stocks?
Index funds are safer; lower volatility reduces DCA advantage but also caps downside. Individual stocks = higher volatility = DCA more valuable. Match strategy to your risk tolerance.
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