A zero based budget gives every dollar of your pay a job before you spend it. Most guides are written for a calendar month. Here is how it works when you are paid weekly or fortnightly.
Written by Alex BPublished 13 November 2026
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A zero based budget is a simple idea: before you spend your pay, you decide where every dollar of it is going. When you add up the plan, your pay minus everything you have given a job comes to zero. Not because you have spent it all, but because nothing is left without a purpose.
Almost everything written about this method assumes you are paid once a month. If you are paid weekly or fortnightly, the same idea works, but there are a few things to do differently. That is what this guide covers.
It does not mean your bank account is empty. It means your plan is complete. Pay, minus bills, minus groceries, minus savings, minus everything else you have decided on, equals zero:
That planned amount includes savings, a buffer, debt repayments and spending money. If you have $80 left over in your plan, it is not done yet. Give it a job, such as the car rego fund or a bit extra on a card. The 50/30/20 rule is a simpler way to split a pay if you would rather start with percentages.
Start with the take-home pay that is about to land. This is the money you are planning. If you are paid fortnightly, the plan is for one fortnight. Using one pay at a time keeps it close to real life, because your bank balance changes on payday, not on the first of the month.
If your pay changes from one pay to the next, plan with your lower usual amount and give any extra a job when it lands. The guide on budgeting on irregular income shows how to find a baseline.
Write down the bills and costs due before your next payday. Rent, car loan and utilities often come first, because they are fixed. Then groceries, transport, kids' costs, phone and the rest. The safe to spend guide covers how to separate what is committed from what is genuinely yours.
This is the part monthly-based guides skip. Some bills do not land in every pay: a quarterly electricity bill, yearly rego, the monthly phone plan when you are paid fortnightly. If you only budget for them in the pay they hit, that pay is squeezed and the others look rich.
Instead, give each pay a share. Multiply the bill by how many times a year it is charged, then divide by the number of pays in the year:
For example, a $150 monthly bill on a fortnightly pay is $150 × 12 ÷ 26, about $69.23 a fortnight. A $390 quarterly bill is $390 × 4 ÷ 26, which is $60 a fortnight. Money you set aside this way waits for the bill in a separate place. The sinking funds guide explains how, and fortnightly budgeting with monthly bills covers the extra pays some months bring.
Once the bills and their shares are in, look at what is left. Decide, in this order:
Keep going until the figure left is zero. If you cannot reach zero because the bills already cost more than your pay, that is useful information too. It is better to find out before the pay is spent.
| Job | Amount |
|---|---|
| Rent | $1,000 |
| Groceries | $420 |
| Fuel and transport | $150 |
| Share of monthly bills (phone, internet, insurance) | $210 |
| Share of quarterly and yearly bills | $130 |
| Kids' costs | $110 |
| Buffer | $100 |
| Savings goal | $100 |
| Spending money | $380 |
| Total given a job | $2,600 |
$2,600 minus $2,600 is zero. Nothing is unassigned. That does not mean the $380 of spending money has to be spent on a single thing. It is simply the amount that is free to use this pay.
A zero based budget is only a plan. At the end of the pay, compare it with what you actually spent. If groceries cost $470, you will know before the next pay, and you can move money from spending to groceries instead of letting it slowly drain the buffer. Budget vs actual shows the method.
A done-for-you shortcut: Payday Buffer starts from your pay, takes off the bills due before your next payday, essentials and upcoming costs, and gives you a Safe to Spend estimate. It works the other way round from a strict zero based budget, but it answers the same question of what each pay has to cover. For a category-by-category plan compared with real spending, Fortnightly Budget Plus lets you set an amount for each category and savings goals alongside it. Both are Excel workbooks and neither connects to your bank.
For a free start, the Free Fortnightly Budget has 23 categories and shows what is left in your plan after bills, spending and savings, so you can see when you have reached zero. The free Payday Check gives a quick safe-to-spend estimate.
No. Savings and buffers are jobs too. You are deciding where every dollar goes, and spending is only one of the options.
Move money from another job, and note why. If it happens often, the plan is the problem and not you.
Yes. Plan one week, and give each bill a weekly share using the same formula with 52 pays a year.
This article provides general information only. It does not take into account your personal objectives, financial situation or needs, and it is not financial advice. Examples use invented figures. Money Detective's tools provide estimates and planning information. Consider your own circumstances, and seek independent advice if you need it, before making financial decisions.