Why it helps
Most of us know roughly what we earn and roughly what the rent or mortgage is. The rest gets fuzzy: some bills are weekly, some fortnightly, some once a year, and the bank balance never quite matches what you thought.
AI can take your rough numbers, put them all on the same monthly footing, and lay them out in a simple budget. It's good at spotting the things people forget, like car rego, birthdays and the dentist, and at suggesting practical savings ideas to try. You stay in charge of the real numbers and the decisions.
The prompt
Copy it, swap the bits in [square brackets], and paste it into ChatGPT, Claude, Gemini or Copilot.
Help me build a simple monthly household budget. I'm in New Zealand, so use NZ English and NZ examples. Here's my rough income and spending. Some amounts are weekly, fortnightly or yearly, so please: 1. Convert everything to a monthly amount and show how you did it (weekly x 52 / 12, fortnightly x 26 / 12, yearly / 12). 2. Put it in a table grouped into: Income, Housing, Bills, Food, Transport, Kids, Fun and takeaways, Savings, Other. 3. Show total income, total spending and what's left over each month. 4. List costs that people often forget, and ask me if I've included them. 5. Suggest 5 practical savings ideas based on my numbers. Keep them realistic for a normal Kiwi household. Rules: - Only use the numbers I give you. Don't invent income or costs. - This isn't financial advice, so don't tell me what to invest in or which loans to take. My numbers: [list your take-home pay and spending, with how often each is paid]
Then keep chatting
Give me this as a table I can paste into Google Sheets, with formulas for the totals.
Work out how much I'd need to put aside each fortnight to cover the yearly costs.
What if I cut takeaways in half and moved that to savings? Show me over 12 months.
Make me a simple weekly spending check-in I can do in 5 minutes.
Step by step
- Look at a month or two of your bank app and jot down rough amounts and how often each is paid. Round numbers are fine.
- Add the yearly or irregular costs you can think of: car rego and WOF, insurance, Christmas, birthdays, school costs.
- Paste the prompt with your list. Don't include account numbers or names.
- Check the monthly conversions with a calculator, and check the totals add up.
- Pick one or two savings ideas to try this month, and check your progress in a few weeks.
Worked example
Example details are made up. Your results will vary, so always read and check before you use them.
Watch out for
- Privacy: never paste bank account numbers, card numbers, your IRD number or full bank statements. Rough amounts and categories are all the AI needs.
- Check the maths. AI can make arithmetic slips, so check the conversions and totals with a calculator or put them in a spreadsheet.
- This isn't financial advice. For debt, KiwiSaver or investing, use Sorted.org.nz or a licensed financial adviser. If money is really tight, MoneyTalks (moneytalks.co.nz) and local budgeting services offer free, confidential help.
- Savings ideas are general. Check any power, phone or insurance switch yourself, including contract terms and break fees.
Go further
Sorted.org.nz has free budgeting and savings tools built for New Zealanders, and it's a good next step once you've got your rough numbers. If you want to keep your budget in a spreadsheet, the [spreadsheet formula helper](/use-cases/spreadsheet-formula-helper) can write the totals and monthly conversions for you.
