How an income shock simulator works, and why month-by-month beats a single 'runway' number
TL;DR: An income shock simulator models a specific drop in income (a pay cut, job loss, or lost bonus) against your real expenses month by month, showing the deficit, how your reserve depletes, and — only if you explicitly model one — how a recovery income would change the picture. It's more useful than a single "runway" number because it shows exactly when things would get tight, not just whether they eventually would.
What goes into a realistic simulation
- The size and type of the shock — a full job loss, a partial pay cut, or a lost bonus/overtime each have very different monthly deficit sizes.
- Duration — whether the shock is temporary (a few months) or open-ended changes the total damage significantly.
- Your actual essential expenses — not total spending, since some costs would likely be cut during a real shock.
- Any recovery income — modeled explicitly, never assumed, since assuming a recovery date that isn't real would make the simulation misleading.
Why the month-by-month path matters more than a single number
Two households can have the same "6 months of runway" but very different risk profiles — one whose deficit is small and slow-building versus one whose deficit is large and immediate. The month-by-month path reveals which situation you're actually in, including the specific month your reserve would hit zero, if it ever does.
How to use the output
The most actionable numbers are the minimum reserve point and the month it occurs — if it stays comfortably positive, your buffer is adequate for that specific shock size; if it goes negative, you know exactly how much runway you're short by and how urgently you'd need a new income source or a bigger expense cut.
Run your own income shock scenario
Our free Income Shock Simulator models this month by month using your real numbers, without inventing a recovery date it can't justify — showing you the honest deficit and reserve path for the scenario you actually specify.
Frequently asked questions
What does an income shock simulator actually calculate?
It models a specific drop in income — like a job loss or pay cut — against your real expenses over time, showing the monthly deficit and how your cash reserve depletes month by month, rather than a single static 'runway' figure.
Why is month-by-month better than just knowing my runway in months?
Because it shows exactly when the deficit would start to bite and whether your reserve would ever actually go negative, which a single averaged number can hide — two households with the same runway number can have very different real risk depending on the shape of that deficit over time.
Does an income shock simulator assume I'll find new income by a certain date?
No, not unless you explicitly add that as a modeled recovery income — a responsible simulation won't invent a recovery timeline it has no basis for, since doing so would make the results misleadingly optimistic.
What should I do if my simulation shows my reserve going negative?
It tells you exactly how much shortfall you're facing and when — useful information for deciding whether to build a larger reserve now, reduce fixed obligations, or have a specific backup income plan ready before a real shock happens.