Learn the basics
The financial playbook
you were never handed.
Plain-language answers to the most important investing questions. No jargon. No agenda. Just the information your grandmother deserved to have — and that you have access to right now.
Start here
Four concepts. That's all you need.
Most people who invest successfully for a lifetime understand a small number of ideas deeply — not hundreds of concepts shallowly. These four are the foundation of everything else.
What is a stock?
A small piece of ownership in a company. When the company grows in value, your piece grows with it. The building block of every index fund — and the reason consistent investing builds wealth over time.
Read the full definition →What is an index?
A way of measuring how a group of companies is performing together as a single number. The S&P 500 is the most important one — tracking 500 of America's largest companies. Understanding it unlocks the most powerful investing tool on this site.
Read the full definition →What is an index fund?
An investment that automatically owns a piece of every company in an index — at almost no cost. The tool the grandma calculator is built around. More than 90% of actively managed funds fail to beat a simple S&P 500 index fund over 20 years.
Read the full definition →What is a bond?
A loan you make to a company or government that pays you back with interest on a fixed schedule. Steadier than stocks, slower to grow. Becomes more important as you get closer to retirement and want to protect what you've built.
Read the full definition →Suggested path
If you're starting from zero
You don't need to read everything at once. Here's the order that makes the most sense if you've never thought about investing before.
Run the calculator first
Before anything else, use the grandma calculator on the home page. Let the numbers land. That's what makes everything else feel worth learning.
Go to the calculator →Understand what a stock is
A five-minute read that explains what you actually own when you invest — and why it builds wealth over time.
What is a stock? →Learn what an index is
Once you know what a stock is, understanding an index takes about two minutes — and sets up the most important concept on the site.
What is an index? →Read about index funds
The tool the grandma calculator is built around. The most important thing to understand before you open your first account.
What is an index fund? →Open your first account
You now know enough to start. The brokers page shows you where to open a free account and what to buy first — step by step.
Where to invest →See it in action
Now run the numbers.
The grandma calculator shows what consistent investing in a simple S&P 500 index fund produces over decades — using real historical returns going back to 1950. Let the math do the rest.
Run the calculator →