How the Stock Investment Simulator Works
The goal of the simulator is to answer one question clearly: if you had invested in a given stock or index over a given period, what would the historical result have looked like? This page explains exactly what the calculator does, step by step, and what it deliberately leaves out.
1. Choose the asset and dates
Select one stock or index and a historical period that the dataset supports. The simulator uses monthly closing-price data inside that range. Available assets include Tesla (TSLA), NVIDIA (NVDA), AMD, Palantir (PLTR), the S&P 500, the KOSPI index, Samsung Electronics, SK Hynix, and Hanwha Aerospace.
2. Choose your investing pattern
You can model a one-time starting deposit, recurring monthly contributions, or a combination of both, to match how many people invest in practice. Setting the monthly contribution to zero produces a pure lump-sum simulation; setting the starting deposit to zero produces a pure dollar-cost-averaging simulation.
3. Compare invested cash to ending value
The output separates total cash invested from estimated portfolio value, so it is easy to see contribution size, gain, and accumulated shares. The Chart.js line chart plots cash invested in teal and portfolio value in gold, side by side.
What is included
Historical monthly price changes, date-range filtering, lump-sum investing, recurring monthly buys, and fractional-share allocation at each monthly close.
What is not included
Taxes, dividends, trading fees, slippage, bid/ask spreads, account-specific rules, fractional-share restrictions imposed by individual brokers, or any forward-looking prediction. These exclusions are explicit in the UI and in the linked guides.
Why the simulator uses monthly closes
Monthly closing prices keep the dataset compact, easy to audit, and consistent across stocks and indexes. Daily data would shift the calculation from "what did this asset do over this stretch of months" to "what would this exact trade have done", which depends heavily on intraday execution that retail investors usually cannot match.
Use the simulator as a learning and planning aid. Verify taxes, fees, dividends, and suitability with primary sources or a qualified professional before acting.