Guides & walkthroughs
Understand the math behind your money
Each guide explains one financial concept in plain language, walks through the numbers by hand, then hands you a free calculator to run your own figures. From your first emergency fund to your company's runway, no spreadsheets and no accounts.
How to build an emergency fund
How big the fund should be, the months formula, and the step order that makes the habit stick.
Read the guideMoney dos and don'ts
The habits that actually move the needle: what to automate, what to avoid, and the rules of thumb in between.
Read the guideCommon money mistakes
The financial downfalls that sneak up on you, from lifestyle creep to timing markets, with the fix for each.
Read the guideBest personal finance books
The one idea each well-known book teaches, and which book to pick for the problem you have right now.
Read the guideInterest rates and inflation
How the market moves your money: savings yield, debt cost, buying power, and the three signals worth reading.
Read the guideHow to calculate startup runway
The exact formula, a worked example, and what 12 months of runway actually means for fundraising.
Read the guideHow much is a company making? 7 ways to estimate revenue
Estimate any company's revenue without internal numbers - from pricing, public filings, headcount, traffic and unit economics.
Read the guideHow to calculate LTV:CAC for a subscription business
Customer lifetime value, acquisition cost and payback, with the 3:1 rule explained through worked numbers.
Read the guide
Skip the reading, run the numbers
Every guide ends in a free calculator. Browse all eighteen tools or open the full business model simulator that connects them.