Turn irregular yearly costs into monthly figures and test budget scenarios with ChatGPT

Posted

Sep 18, 2026 by Matt Sosland (LinkedIn)

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Last checked

Oct 17, 2026

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Method:

How we verify

Evidence: Described by posterThe person describes what happened in words, without screenshots or video.

Context: The poster is a financial professional who offers a related guide.

Outcome

A poster used ChatGPT to organise his family's full budget, including annual costs, insurance, kids, subscriptions and irregular expenses, converting irregular costs into monthly averages, spotting blind spots and running scenarios. He says it was useful for organising and scenario planning but didn't replace judgment or professional advice.

Agent

ChatGPT

The source didn't share its exact prompt, so we wrote this from what it describes.

Before you start, ask me 1–3 short questions about anything important that's missing below. Keep them quick. Then do the task, checking in with me at the key points.

Goal: Build a complete household budget that includes irregular and yearly costs, then test a few what-if scenarios.

What I can give you (ask for whatever's missing):
- Monthly bills and income
- Yearly or irregular costs (insurance, car, holidays, school)
- Upcoming big decisions

Rules:
- Convert every irregular cost to a monthly amount and show the math.
- List common costs I may have missed and ask if they apply.
- Run 2-3 scenarios I name and show the monthly effect.
- Keep it as an organizing tool; note when a professional should check.
- If a site asks for a login, a CAPTCHA or payment details, stop and hand control back to me.
- Ask for my OK before you pay, book, send, submit or cancel anything.
- Check facts that can change (prices, opening hours, dates, availability, rules) against the official source, and tell me anything you couldn't verify.

Output: A full monthly budget table, a blind-spot list and a scenario comparison.

You'll know it worked when: the budget accounts for every cost we expect this year.

Before you start, ask me 1–3 short questions about anything important that's missing below. Keep them quick. Then do the task, checking in with me at the key points.

Goal: Build a complete household budget that includes irregular and yearly costs, then test a few what-if scenarios.

What I can give you (ask for whatever's missing):
- Monthly bills and income
- Yearly or irregular costs (insurance, car, holidays, school)
- Upcoming big decisions

Rules:
- Convert every irregular cost to a monthly amount and show the math.
- List common costs I may have missed and ask if they apply.
- Run 2-3 scenarios I name and show the monthly effect.
- Keep it as an organizing tool; note when a professional should check.
- If a site asks for a login, a CAPTCHA or payment details, stop and hand control back to me.
- Ask for my OK before you pay, book, send, submit or cancel anything.
- Check facts that can change (prices, opening hours, dates, availability, rules) against the official source, and tell me anything you couldn't verify.
- Mark which numbers are estimates so I can replace them with real figures.

Output: A full monthly budget table, a blind-spot list and a scenario comparison.

You'll know it worked when: the budget accounts for every cost we expect this year.

Before you finish: re-read my goal and constraints, check your answer against each one, and list anything you assumed or couldn't confirm.

Source

https://www.linkedin.com/posts/matt-sosland_i-spent-some-time-this-week-building-out-activity-7506789447821094912-r2TC