Guides

Three chained calculations turn retirement anxiety into a number: the target, the inflation correction, and the monthly price of each decade of delay.

The single-division formula everyone quotes and the three silent decisions inside it: gain, cost, and time, with worked examples.

One product, two percentages: why a 40% margin is a 66.7% markup, and how applying the wrong one quietly costs seven points of profit.

Convert between hourly pay and annual salary in both directions, and catch the assumptions that make two similar offers very different.

The erosion table for idle money, the real-return formula, and why a plan that ignores inflation aims at half the true target.

Snowball or avalanche? One realistic three-debt example simulated month by month shows the real gap in time, interest, and motivation.

The mortgage formula explained digit by digit on a real $300,000 example, plus PITI, PMI, 15 vs 30 years, and how much extra payments save.

See exactly how each loan payment splits between interest and principal, year by year, and why the early years belong to the bank.

The compound interest formula worked through real numbers: frequency, monthly contributions, the Rule of 72, and why starting ten years earlier wins.