Most personal finance tools quietly assume returns compound at 10% forever, bury inflation behind a toggle nobody finds, and hide their methodology behind a “learn more” link that goes nowhere. Fin Folk Tales takes the opposite approach: every assumption is visible, every formula is documented, and every default rate links to where it comes from.
All nine calculators work with no account, no sign-up, and no network call — change any input and the result updates immediately. Save a scenario to this browser if you want to keep it, or sign in to sync it to your account; otherwise nothing you type is stored anywhere.
The writing
The essays work through specific financial decisions — paying down debt versus investing the difference, what a retirement plan looks like at different savings rates, and similar — grounded in real numbers rather than general advice. The full list is on the Writing page.
What we won't do
- Ask for a bank login — or store an account number, routing number, or SSN, even if you type one. Rejected at the database, not the form.
- Place an affiliate link inside your plan or vault. The recommendation surface stays clean as a rule, not a preference.
- Hide a formula — or let a model guess at your recommendations. Every task comes from a rule you can read.
- Require an account to run a calculator. All nine work with zero network calls. Sign in only if you want to sync.
Data & privacy
Plan and Vault are the only parts of the site that require signing in, since they save information across visits. What they can store is restricted at the database level, not just hidden in the interface — account numbers, routing numbers, Social Security numbers, card numbers, and full dates of birth are all rejected outright, regardless of what's typed in. There's no bank account linking and no live market data feed. See the Help page for the full breakdown of what's stored and what isn't.