Put in your monthly take-home pay and the 50/30/20 rule splits it three ways: half goes to needs, 30% to wants and 20% to savings. On $4,200 that is $2,100 for needs, $1,260 for wants and $840 for savings. Add what you spend now and the calculator shows what to move where, for one income or two.
Showing an example of $4,200 a month. Type your own figure or turn the dial.
What reaches your account after tax. Add back a pension or health plan taken out before it arrives.
$2,100
Rent or mortgage, utilities, groceries, insurance, transport to work, childcare, minimum debt payments.
$1,260
Eating out, streaming, holidays, hobbies, clothes beyond the basics, upgrades.
$840
Emergency fund, pension, investments, and debt paid above the minimum.
Put in what you spend now on each part and the moves appear here.
Shared in proportion to pay: each of you puts the same share of your own pay into each part.
This is the page that prints. It updates as you change the figures above.
Month
Take-home payCombined take-home pay
$4,200 · Example figures
Person 1 $4,200 + Person 2 $0
| Part | Rule | Target | Now | Difference | After moves |
|---|---|---|---|---|---|
| Needs | 50% | $2,100 | |||
| Wants | 30% | $1,260 | |||
| Savings | 20% | $840 |
Write in what you spend now, then check it against the target.
| Part | Person 1 100% of the pay | Person 2 0% of the pay |
|---|---|---|
| Needs | $2,100 | $0 |
| Wants | $1,260 | $0 |
| Savings | $840 | $0 |
The link carries every figure on this page, so whoever opens it sees the same budget. Anyone with the link can see the amounts.
Elizabeth Warren, then a Harvard law professor who studied family bankruptcy, and her daughter Amelia Warren Tyagi set out the rule in All Your Worth: The Ultimate Lifetime Money Plan, published by Free Press in 2005. They call it the Balanced Money Formula: Must-Haves 50%, Wants 30%, Savings 20%. In their words, Must-Haves are "the things you will have to pay no matter what", and they are recurring payments that stay about the same each month. The name "50/30/20" came later, as banks, newspapers and calculators like this one took the rule up.
Elizabeth Warren and Amelia Warren Tyagi, All Your Worth: The Ultimate Lifetime Money Plan (New York: Free Press, 2005), ISBN 978-0-7432-6987-2.
Bills you would still have to pay if you lost your job tomorrow: housing, utilities, groceries, insurance, getting to work, childcare you need in order to work, and the minimum payment on every debt.
Everything you choose: meals out, subscriptions, holidays, gym memberships, gifts, the nicer version of a need. A test: if you could stop it this month without breaking a contract, it is a want.
Money that leaves you better off next year: an emergency fund, pension or retirement contributions, investments, and any debt paid off above the minimum.
Your figures travel in the page address, so the share link is the way to keep them. There is no account to make.
The targets are plain percentages of the take-home pay you enter: needs are half of it and wants are 30%, each rounded to the nearest whole unit, and savings are whatever is left, so the three always add back to the income exactly. With two incomes the two figures are added first and the total is split. Each person's part of each bucket is their share of the combined pay: person one's part is rounded and person two takes the rest.
If you put in what you spend now, each figure is held against its target and shown as a share of income, to one decimal place. A blank spending box counts as zero once any of the three has a number in it. The moves are worked out in a fixed order. First, spending above take-home pay comes out of wants, as far as wants go. Second, money you have not assigned to any part is sent to savings. Third, if wants are above 30% while savings are below 20%, the excess moves from wants to savings, up to what savings need. Fourth, if savings are still short, needs must be above half: wants cover the gap for now, and the needs overrun is named as the lasting fix. Nothing is moved out of needs, because a need cannot be cut by moving a number.
The dial runs from nothing to 15,000 a month in steps of 50; typing a figure takes any amount up to ten million. The currency sign changes the sign and nothing else — no amounts are converted. The rule itself is Warren and Tyagi's. The order of the moves, and treating payments above a debt's minimum as savings, are our reading of it, not the book's words. Your figures travel in the page address, which is how the share link carries the whole budget; there is no account.
Every figure above was read out of the code that runs on this page. Where a number is our own judgement rather than a published one, the note says so and cites nothing. Method last checked 28 September 2026.
Most budgets fail at the setting-up stage: twenty categories, each needing a number nobody knows, and a spreadsheet that goes quiet by the second month. The 50/30/20 rule asks for one number — what you bring home — and gives back three. It works because the three parts are the three decisions that matter. Needs are what the household has already committed to. Wants are where day-to-day choices happen. Savings is whatever the household keeps for next year.
The rule is also a test. Put in what you really spend and the calculator shows which part is out of shape. Needs over half often come down to one large line — rent or a car payment — rather than to a hundred small ones, and no amount of skipped coffee fixes a rent that is too high. Wants over 30% is the part you can change this month.
To find your needs figure, start with the bills. Our household bills calculator adds up rent, electric, gas, water, internet, phone and the rest into one monthly total: that total, plus groceries, transport and minimum debt payments, is the needs number to put in here. Our guide to a shared household budget covers the monthly review that keeps the numbers honest, and if two of you earn different amounts, the family expense fairness calculator splits the shared bills in proportion to income.
Add up every household bill — rent, electric, gas, water, internet, phone — for a monthly and yearly total, the cost per person, and how you compare to average.
Calculate a fair bill split based on each person's income. Perfect for couples, blended families, and households with unequal earnings.
Split grocery costs between roommates or family members. Tag items as shared or personal, and see exactly who owes what. Free, no signup.
Homsy keeps shared expenses, bills, lists and the family calendar in one app everyone in the house can see.
