Methodology

How the numbers are worked out.

DebtShield is educational and transparent. Its thresholds are documented heuristics, not universal financial facts — and the app shows its assumptions on every card.

The Safe Line & verdict

The Safe Line compares your essentials to your income against a documented guideline (about 55% of income). The verdict combines that share with your remaining dollar cushion, your debt-payment load (using the common 20% watch / 36% heavy rules of thumb), and your recent trend. These are configurable heuristics — helpful guidance, not absolute truth.

The year-ahead simulation

DebtShield runs a Monte Carlo simulation of your next 6 and 12 months:

Hundreds of runs. Each month, income and each cost vary around your figures, plus an occasional surprise expense.
Where the spread comes from. Once you've tracked at least three months, the variation is measured from your own history; before that, it uses typical national month-to-month variation — and the app tells you which.
What you get. A probability of dipping into the red, a likely range (10th–90th percentile), and the single change that reduces the odds most.
Deterministic. A fixed seed means the same numbers always produce the same result. It runs off the main thread so the app stays responsive.

We never tune assumptions to make risk look more dramatic. A projection is a projection — shown with its range and its assumptions, never as a certainty.

Assumptions & limitations

It can't see your full situation — only the figures you enter.
Benchmarks are broad public averages, not your exact costs.
The simulation assumes your future roughly resembles your recent past, which real life can break.
It is not advice and does not predict or guarantee any outcome.

The full threshold registry and engine methodology live in the open-source repository alongside the app's unit tests.