About

#What this is

ETF Stock Calculator is a free tool for backtesting dollar-cost averaging plans across real ETFs and stocks, using actual historical daily price data, not a simplified compound-interest formula. You pick tickers, a contribution plan, and a time period. It shows what that plan would actually have been worth today.

#Why I built it

I'm Kevin, a software engineer with a background in AI and agent development. I've always been interested in investing and compounding growth. Most calculators I used online let me enter a fixed return rate to simulate, or could only handle one ticker at a time. I wanted something that could compare multiple ETFs and stocks side by side and show me how much of the final value came from my own contributions versus actual market gains. So I built one. This calculator runs a real day-by-day simulation, and I want to share it with other investing enthusiasts.

Accurate results matter to me, so I focused on getting details like reinvesting dividends properly and using IRR instead of simple CAGR, so the timing of each contribution is actually accounted for. Using my AI background, I also added the ability to generate a plain-English analysis after each run, summarizing what each ticker is and explaining how they compared.

The site is a solo project, built and maintained by me. It isn't backed by a brokerage, fund company, or financial institution.

#How it stays trustworthy

Every number this tool produces comes from a documented, deterministic calculation. There is no black box. The How It Works page walks through exactly how price data is sourced, how dividends and stock splits are handled, and how the annualized return (IRR) is calculated, including the exact formulas and solver used. If you want to verify a result by hand, everything you need is on that page.

The tool is for education and research, not financial advice. It shows what would have happened historically under a given plan. It doesn't predict the future, and past performance never guarantees future results. Always consult a qualified financial advisor before making investment decisions.

#How the site is funded

ETF Stock Calculator is free to use, with no account or sign-up required. It's supported by display ads (Google AdSense) and affiliate links to brokerages. If you open an account through an affiliate link, the site may earn a commission at no cost to you. Affiliate relationships never influence the tool's data or calculations. The simulation logic is identical regardless of which links you click.