Scheduled investing (DCA) is as much about sticking with a plan as about averages. Lump sums often win on paper; regular contributions win when they keep you invested.
Dollar cost averaging (DCA) calculator.
Practical tip Start with round numbers from your bank or contract. You can refine decimals after the first pass.
What to enter
Have these handy before you start. Names vary by tool, but the ideas are the same.
Starting amount (lump sum or current balance)
Contribution amount and frequency (monthly is common)
Expected annual return and how often interest compounds
Time horizon in years
Quick workflow
Enter your starting point and contribution plan.
Set return and compounding to match the product you are modeling.
Compare two scenarios (for example base vs +1% return).
Free calculator Use the DCA calculator to compare periodic buys versus a lump-sum entry over the same horizon and volatility assumptions.
Worked example (illustrative)
You have $12,000 to deploy and plan $500/month for 24 months while the asset drifts upward with volatility. Lump-sum investing on day one captures the full rally if prices rise steadily; dollar-cost averaging smooths the average purchase price when prices swing—sometimes beating lump sum, sometimes lagging. Over 24 months at $500/month you invest $12,000 either way; the difference is timing risk, not magic. Model both paths in the DCA calculator with your expected return and volatility—not a prediction of VTSAX or any fund.
Common search questions
DCA calculator — compare dollar-cost averaging vs lump sum over your horizon.
Dollar cost averaging calculator — smooth entry price with periodic buys.
VTSAX calculator — model recurring contributions to index funds over time.
Open the tool when you already have a quote, a deadline, or a what-if and need a clear number for investing.
Situations people use it for
You want to compare two monthly contribution plans before locking in this year
You are explaining to someone why a small extra deposit each month adds up
You have a return assumption from a fund fact sheet and want a quick check
How to read the result
Treat the output as a structured estimate. Small input changes should move the result in a direction that makes sense.
Run a conservative case first. If it still works, you have margin.
Change one field at a time so you know what actually moved the number.
Save the scenario with a name you will recognize later ("2027 refi", "15-year plan").
This model assumes: Dollar cost averaging (DCA) calculator.
Common slip-ups
Using nominal returns when you mean to think in real (after-inflation) terms
Forgetting fees and taxes compound against you too
Treating past performance as a guarantee in the slider
Try it with your numbers
Open the DCA calculator, enter your case, and keep a screenshot or PDF if you will revisit the decision. Everything runs in your browser; your inputs are not sent to our servers for the math.