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Why Build the Investment Calculator

At Golden Door, we built the Investment Calculator as an internal valuation tool. When I started on Wall Street, I remembered every investor had the HP 12C Financial Calculator on their desk. It was a powerful, handheld device.

Of course, when investing there are only a few important variables worth noting: present value, payments, interest rates and future value.

When you sit on a trading floor, accuracy of these 3-4 variables are essential when investing. As remote work became popularized and people started investing more often, I realized the physical calculator became obsolete. Instead, investors would use spreadsheets to do quick math. Myself included.

The problem with spreadsheets is if you are not a financial expert, then you probably don’t have a valuation model ready made. You probably don’t know the best websites to use for financial calculations. Personally, I was tired of opening up so many tabs for simple calculations. Which is why I built the Investment Calculator as a Chrome Extension.

How to Use the Investment Calculator

The Investment Calculator is designed for quick stock analysis. Realistically you can input any number but you will notice that it defaults to stock data. In the first tab, you can input any ticker and retrieve the name, price and market cap. The company overview was critical for me. I found myself reopening Yahoo Finance multiple times per day for a company summary.

(The computer-like font in the first three rows is a node to the Bloomberg Terminal. I liked this font style because we focus on technology and it reminds of the command interface)

The second tab is for the fifteen calculators. These are the current defaults. In the future, we will add more with more functionality.

15 Calculations for Investors

Here is a list of the current calculators in the chrome extension. I prioritized the most common ones like Return on Equity and Capital Gains. These are functions investors are assessing quite often.

The Return on Investment calculation is most common when making decisions. Below you can see the Initial Investment was $100 and the Final Value was $190. On the surface, this is a simple formula but let’s not forget that some people aren’t great at simple math.

Instead when you add more realistic stock prices, the calculator becomes more helpful.

Who is the Investment Calculator built for?

Everyday investors and traders will use this Investment Calculator. It is designed for quick analysis. I’m sure daytraders will maximize the position sizing for intraday positions. Myself, like other value investors, will focus on the compounding calculations.

When computing valuations, I’ve always found scenario analysis tools to be most helpful when making investments. For example, if I want to understand the risk and reward of a stock price, I want to test for time and interest rate variations. Interest rates are essential when it comes to investing. So if I can quickly calculate the difference between 5% and 7% on my future value, I can make a more educated decision.

Right now, the Investment Calculator is a simple and powerful tool. It is not designed to make investment recommendations. Instead it is an analysis tool to help you make more educated investment decisions.