Financial case studies
See the numbers become a plan
Detailed, believable walkthroughs that connect a real-life money problem to the calculators, guides, assumptions, and trade-offs behind the answer.
8
cases
14
calculators
15
guides
Transparent numbers, practical decisions
Each case shows its inputs, assumptions, and modeled results alongside the linked tools, so you can trace the reasoning and replace the figures with your own.
How to use these stories
Follow the reasoning, then replace the inputs
A case study is useful when you can see where every number came from, which assumption carries risk, and which part needs to change for your own life.
Start with the tension
Each story begins with the practical question the person is trying to answer.
Trace every number
Inputs and modeled results link directly to the calculator that produced them.
Read the rule behind it
Related guides explain why the plan protects one trade-off before another.
The case-study library
Choose the situation closest to yours
The budgets, rates, constraints, and imperfect decisions are deliberately ordinary.
Sofia Mendes
Porto, Portugal
How Sofia Made an Uneven Income Feel Predictable
Sofia did not need a better average. She needed a plan that still worked when two quiet weeks landed in the same month.
Monthly take-home range
€1,800–€4,400
Essential monthly costs
€2,050
Miguel Rocha
Braga, Portugal
How Miguel Put a 19.4% Credit Card on a Clock
Miguel’s breakthrough was not a dramatic cut. It was finding an amount small enough to repeat and large enough to change the finish date.
Credit-card balance
€6,800
Card APR
19.4%
Inês & Tomás
Coimbra, Portugal
How Inês and Tomás Protected €14,000 for a Home
Their first deposit number looked close because it quietly counted every euro they owned. The safer plan began by deciding which money was not for sale.
Target property price
€250,000
Current house fund
€18,000
Marta & Diogo
Lisbon, Portugal
How Marta and Diogo Made Shared Costs Feel Fair
Their argument looked like it was about supermarket receipts. The real problem was that they had never agreed what “half” was supposed to protect.
Shared monthly costs
€2,300
Marta’s take-home income
€3,200
Beatriz Lopes
Aveiro, Portugal
How Beatriz Turned Subscription Clutter into €3,000
No single charge looked serious. Together, eleven quiet renewals were consuming the exact margin Beatriz said she could never find.
Recurring services
11
Monthly subscriptions
€142
Daniela Pires
Setúbal, Portugal
How Daniela Built Rules Before Picking Funds
Daniela thought her first decision was which fund to buy. The more durable decision was what the money was for and how she would behave after buying it.
Initial investment
€4,000
Monthly contribution
€250
Rita Nunes
Lisbon, Portugal
How Rita Set a Rent Ceiling Without Dropping Savings
Rita could technically pay the advertised rent. Her harder question was whether she could pay it without quietly cancelling every other priority.
Monthly take-home pay
€3,200
Flat initially considered
€1,050 / month
Paulo and Helena Costa
Faro, Portugal
How Paulo and Helena Balanced Cash and Mortgage Debt
Paulo and Helena wanted the certainty of owing less without turning a strong cash balance into a fragile household.
Mortgage balance
€165,000
Rate / remaining term
3.7% / 24 years