Guides
Plain-language articles on FIRE, investing, mortgages, taxes, and net worth — written to support our free calculators. 8 guides and growing.
FIRE & Retirement
What Is FIRE? Financial Independence, Retire Early Explained
Learn what FIRE means, how the 4% rule works, and how to estimate your FI number before using a FIRE calculator.
The 4% Rule Explained: Safe Withdrawal Rate for Retirement
What the 4% rule means, where it came from, its limits in today's markets, and how to use safe withdrawal rates in FIRE and retirement planning.
Investing & Savings
Savings Rate: What It Is, How to Calculate It, and Why It Matters
Learn how to calculate your savings rate, benchmark against FIRE targets, and see how raising your rate shortens the path to financial independence.
Compound Interest Explained: How Your Money Grows Over Time
Learn how compound interest works, why time and contribution rate matter more than return chasing, and how to project long-term investment growth.
Housing & Mortgages
Rent vs. Buy: How to Decide If You Should Buy a Home
Compare renting vs. buying a home with break-even analysis, opportunity cost, closing costs, and maintenance — and when each option makes financial sense.
How Mortgage Payments Work: Principal, Interest & Amortization
Understand monthly mortgage payments, amortization schedules, PMI, escrow, and strategies to pay off your loan faster with less total interest.