Dollar-cost averaging (DCA) means investing a fixed amount at regular intervals regardless of price, which smooths out volatility and removes the need to time the market. This tool simulates a random price path between your starting and ending price (using the volatility setting to control randomness) and compares your DCA result against investing the entire lump sum on day one. Note: this is a simulation for education purposes, not a prediction — real markets can behave very differently.