Most personal finance writing has the same problem: it tells you what to do without ever showing the arithmetic. You are told to build an emergency fund, avoid bad debt, start investing early — and left to work out what any of that means for your actual salary.
This book takes the opposite approach. Every concept arrives attached to a calculation you can reproduce, and every calculation has a free tool on this site that runs it for your own numbers. The subtitle is literal: it is a numbers-first guide.
It also follows three people all the way through. Raj, Maya and Priya appear in Part 1 with a payslip and a bank balance, and are still there in Part 5 with a retirement target. That continuity is the thing a calculator genuinely cannot give you — a single calculator answers one question, but it can't show you how this month's budget decision reaches thirty years forward.
What's inside
Five parts, ordered the way the decisions actually arrive in a life rather than by topic:
| Part | What it covers | Run it yourself |
|---|---|---|
| 1. Money Foundations | Cash flow vs. income, gross-to-net, 50/30/20 and zero-based budgeting, emergency fund sizing, account structure, and the psychology of lifestyle inflation | Budget, Paycheck, Net Worth, Savings Goal |
| 2. Debt & Credit | The five credit-score factors, utilisation, good vs. bad debt, grace periods, the minimum-payment trap with real numbers, loan types, and avalanche vs. snowball | Card Payoff, Debt Payoff, DTI Ratio |
| 3. Investing Basics | Compounding and the Rule of 72, what a stock and a bond actually are, index funds vs. ETFs vs. mutual funds, expense ratios, diversification, and a three-fund portfolio | Compound Interest, Investment, Mutual Fund |
| 4. Taxes & Income | Reading a payslip line by line, marginal vs. effective rate, deductions vs. credits, standard vs. itemised, the employer match, and traditional vs. Roth | Tax, Salary, 401(k), IRA / Roth |
| 5. Long-Term Wealth | The 4% and 25× rules, working backward from a retirement target, rent vs. buy and the break-even horizon, insurance fundamentals, and estate-planning basics | Retirement, FIRE Number, Rent vs. Buy, Mortgage |
It ends with two references you'll actually return to: a consolidated glossary of every term defined in the book, and a quick-reference formula appendix collecting the arithmetic in one place.
Who it's for — and who it isn't
It's written for someone who has income and wants to understand what to do with it, but has never been given the mechanics. If you've ever nodded along to "just max your 401(k)" without knowing what a match actually is, or wondered why your payslip deducts so much more than you expected, this is aimed squarely at you.
It is probably not for you if: you already run a three-fund portfolio and rebalance annually, you're looking for stock picks or market timing, or you need country-specific tax filing guidance. The tax chapter explains how brackets and withholding work — it isn't a filing manual, and it doesn't try to be one.
An honest note on the numbers
The arithmetic in the book is real and reproducible. You can take any worked example and check it against the calculator on this site — that's rather the point of publishing them together.
The people are not real. The book says so plainly in its own disclaimer: Raj, Maya and Priya, and every dollar amount and rate attached to them, are illustrative and fictional, built to demonstrate a method rather than to represent current market rates or promise an outcome. Interest rates, tax brackets and contribution limits change and vary by country — the book tells you to verify current figures against an official source before acting on anything.
And to be direct about what this page is: the book is a paid product published by Venros, which also builds TallyBench. The calculators stay free, with no sign-up, exactly as they are. Nothing in the book is required to use them.