Guides
The reasoning behind the figures — written from building the calculators, and checkable against your own payslip.
A calculator gives you a number. It cannot tell you whether a raise will really leave you worse off (it will not), why your bonus deposit looked so small, what the quoted mortgage payment left out, or which of two job offers is actually better. These cover that part.
Where every tax figure on this site comes from — by document number, with a plain statement of which state figures are exact and which are labelled estimates — is on the methodology page.
- 01
Marginal vs effective tax rate
A raise cannot leave you worse off. Why the bracket myth persists, and what the two rates actually measure.
- 02
Why your bonus looks so heavily taxed
Bonuses are taxed at your normal rate. Only the withholding differs.
- 03
How to read your paycheck
A line-by-line tour of a pay stub, and how to spot the errors that hide in one.
- 04
How to compare two job offers properly
Two salaries are not comparable until you have adjusted for six other things.
- 05
What a mortgage payment actually includes
The quoted payment is not the payment. What the other third is made of.
- 06
What a 401(k) contribution actually costs you
Contributing $200 does not cost you $200. The arithmetic, and where the match fits.
- 07
Self-employment tax, and why freelancers need a higher rate
Why a $60,000 salary and $60,000 of freelance income are not remotely the same money.
- 08
Why minimum payments keep you in debt
A $5,000 balance at the minimum takes over 15 years and costs more than the balance itself.
- 09
The 4% rule, and what it does not promise
A rule of thumb from a study of 30-year retirements, doing work it was never designed for.
Straight to a calculator
If you already know the figure you need: paycheck, mortgage, loan, 401(k), bonus, self-employment tax, offer comparison and credit card payoff.
General educational information, not tax, investment or financial advice. For decisions of consequence, consult a qualified professional.