The 4% rule, explained with real numbers
Where the rule comes from, when it breaks, and what your number looks like at 3.5% instead.
7 min · Updated August 2026
Guides
Money questions, answered with math
Short, worked-example guides behind every calculator. No fluff, no feed — the answer, the numbers, and a calculator to run your own.
How much emergency fund do you actually need?
Three months? Six? A worked example for single earners, families, and freelancers.
6 min · Updated August 2026
Coast FIRE: the math of stopping early
When your portfolio can finish the job without another contribution from you.
6 min · Updated August 2026
Snowball vs avalanche: which payoff order saves more?
Same debts, two payoff orders, a real interest difference — and why the “wrong” one sometimes wins.
8 min · Updated August 2026
Tracking net worth across EUR, PLN and USD
One number from three currencies — without a spreadsheet full of FX formulas.
5 min · Updated August 2026
Mortgage overpayment vs investing the difference
The break-even rate, the honest way to compare, and when overpaying wins.
7 min · Updated August 2026