Budgeting and income calculators

The rule sends half your take-home pay to needs, three tenths to wants and a fifth to saving and extra debt payments. It is a starting shape rather than a target: in an expensive city the needs half is often impossible, and the useful reading is which bucket is crowding out the others. The line between a need and a want is the honest part. A need is something that has real consequences if it stops.

Income measures the flow, net worth measures the level, and only the second one shows whether the years are adding up to anything. A high earner with a leased car and a maxed card can be worth less than a modest earner who has paid down a mortgage for a decade. What matters is not the figure today but its direction, so this is worth recording once or twice a year.

The advertised salary is the easy conversion. The useful one is the real rate: unpaid time on the job, commuting, and the costs a job creates all belong in the denominator. A shorter commute or a remote role is a raise that never shows on a payslip, and comparing two offers on stated salary alone will miss it.

Inflation is a slow, compounding tax on cash. At 3% a year, prices double in about 23 years, which means a salary that never rises is quietly halved over a career. The number that matters in a pay negotiation is the real rise: your raise minus inflation. Anything below the inflation rate is a pay cut written as an increase.

A zero based budget is not a spending limit, it is an assignment exercise: income minus every category equals zero, with saving counted as a category rather than as what happens to be left over. The zero is the point. Money with no job attached is the money that vanishes without anyone deciding to spend it. What this cannot see is timing. It assumes an even month, so a quarterly insurance bill or a two paycheck month will still throw it out, and irregular costs belong in a sinking fund rather than in whichever month they happen to land.

A raise is quoted in gross annual dollars, which is the largest and least useful way to state it. Tax takes its share at your marginal rate, not your average one, so a raise is taxed harder than the salary underneath it. Inflation then takes another share, and what remains is the real monthly change, which is the only figure that shows up in your life. This models tax on the raise alone: it assumes the standard deduction, applies your state rate as a flat percentage of taxable income, and ignores credits that phase out as income rises, which for households near a phase-out can take considerably more than the rates here suggest.

Federal law requires one and a half times your regular rate for hours past 40 in a week if you are a non-exempt employee. Double time is not federal: it comes from state rules or a union contract, so leave the threshold at zero unless you know you have one. The blended rate at the bottom is the useful figure, because it is what your time is actually paid at once the premium is spread over every hour. What it cannot price is the hours themselves. Fifty two hour weeks pay more per week and less per hour of your life than the same annual figure earned in forty.

The rate most people quote is the salary divided by 2,080 hours, and it is wrong in three directions at once. You cannot bill every hour you work, you are not paid for the weeks you take off, and you now pay both halves of payroll tax plus the health insurance and equipment an employer was covering. Stacked up, the honest rate is often close to double the naive one. What this leaves out cuts both ways: income tax is roughly the same on both sides so it is not modelled, half the self employment tax is deductible against income tax, and a business can deduct expenses an employee cannot. Retirement is also missing. An employer match is real pay, and matching it means charging more still.

The second income in a household is taxed on top of the first, so it meets the higher brackets from its first dollar, and it carries almost all of the childcare bill. That is why the cash answer is often much smaller than the salary suggests, and sometimes negative for a few years. It is also why the cash answer is not the decision. Years out of work compound: pay on return is lower, and the gap tends to persist for a decade or more. Retirement contributions and Social Security credits stop, an employer match with them. Childcare costs fall sharply once a child starts school, so a year or two of a thin margin can be the price of a career that keeps its trajectory. Run this again for each year rather than treating one year's answer as the whole picture.