About CoinGarden

CoinGarden builds small, focused, free calculators for personal finance and investing. The goal is simple: help you build intuition about how money grows over time, without signups, paywalls, or noise.

Who builds it

Oğuz Demir — a software engineer in İzmir, Türkiye. One person, writing the words and the code. Not a financial adviser, and this page will not pretend otherwise.

I studied Manufacturing Engineering at Istanbul Technical University and have spent more than four years building web software. Some of that was over a year on fintech products, where my job was the client-side logic and the data consistency behind financial screens. That work is the reason this site is shaped the way it is: I learned early that a number on a screen is worth exactly as much as the code that produced it, and not a cent more.

I am not an economist and I did not study finance. I learned this material the way you probably are — later than I would have liked, from scratch, and while quietly worrying about money. That is the premise of CoinGarden, not a disclaimer attached to it. A site written by someone who found this hard is a different site from one written by someone who never did.

Away from the screen: classical guitar, charcoal drawing, traditional bookbinding, and mentoring middle-school students in mathematics. The last one is probably why every page here is shaped like a lesson rather than a dashboard.

How the numbers are made

Every figure on this site comes from a small calculation engine with its own tests, written before the page that displays it. Nothing is typed into an article by hand and hoped to be right — when a guide quotes a result, it quotes the same engine the calculator runs. That is not a style choice; it is the only way a one-person site can promise accuracy and mean it.

Each tool does one thing and shows its working: not just the final figure, but how much came from what you contributed and how much came from compounding. Where a calculation rests on an assumption, we say so on the page. Where a claim comes from outside the engine, we cite a primary source rather than another blog. The full detail is on our methodology page.

How to read our results

All figures are estimates based on the inputs and assumptions you provide. They are typically nominal — before taxes and inflation — so real-world outcomes will usually be lower. Markets are variable and past performance does not predict future results.

Not financial advice

CoinGarden is an educational resource, not a financial adviser. Nothing here is a recommendation to buy, sell, or hold any investment. For decisions that affect your finances, consult a qualified professional who knows your situation.

A note on the name — I am not the economist

There is a well-known Turkish academic economist called Doç. Dr. Oğuz Demir — a doctorate in economics, an associate professorship, newspaper columns, television. We share a name and nothing else. We are not the same person, and I have no connection to him or his work.

This matters more than a footnote, because a finance site that lets that confusion stand is quietly borrowing credentials it never earned. So, plainly: I am a software engineer, and you can check that for yourself at linkedin.com/in/oguz-demir-engineer. Trust what is on this site because the sources hold up and the maths is testable — not because of a name.

Contact

Questions, corrections, or suggestions? See our contact page.