Income Shock Survival Simulator

What Is an Income Shock?

An income shock is any sudden, unexpected reduction or elimination of income — job loss, illness, economic downturn, or a business failing. Simulating this scenario helps you understand your true financial resilience before a crisis hits.

How to Use This Calculator

Enter your current savings and your essential monthly expenses. The calculator shows how many months you can survive without income, and what a partial income reduction looks like.

What Counts as an Essential Expense?

This is where many people get caught out. Essential expenses are the non-negotiables — rent or mortgage, utilities, food, insurance, minimum debt repayments. It can help to go through last month's bank statement and separate the genuine essentials from the nice-to-haves. Many people find they are spending more on essentials than they realised. That is not a judgment — it is just useful information to have before a crisis, rather than during one. Even a rough figure is worth plugging in here.

Things People Often Overlook

One thing this is may also matter is irregular expenses — annual bills, car repairs, or medical costs that do not show up every month but can derail a survival plan quickly. One approach is to estimate these yearly costs, divide by twelve, and add that figure to your monthly essentials. It gives a more honest picture of how long your savings would actually stretch. The goal is not to alarm you — it is simply to help you see your finances clearly, while there is still time to adapt.

A worked example

With the defaults: total liquid savings of 15,000, monthly essential expenses of 2,500, income reduction of 100, remaining monthly income of 0. The tool returns 6 mo. You can adjust any input and the result updates as you type — no submit button, no reload. That's the real power here: seeing how sensitive the output is to one or two assumptions.

What moves the number most

The result responds to Total Liquid Savings, Monthly Essential Expenses, Income Reduction, and Remaining Monthly Income. Not every input has equal weight. Adjusting one input at a time toward extreme values shows which ones move the result most.

The formula behind this

This calculator divides the total savings (S) by the monthly expense shortfall (expenses minus any passive income) to estimate months of financial runway. It assumes constant monthly expenses, no investment returns, and no changes to the income or spending patterns. Results represent a simplified illustration, not a guarantee of actual outcomes. Everything the calculator does is shown in the formula box below, so you can check the math against your own spreadsheet if you want.

What the result tells you

The calculation distils your inputs into a single figure. Its value is in seeing how that figure shifts as the inputs change.

What this doesn't capture

The result reflects only the inputs you provide and the assumptions built into the formula. It is a simplified model rather than a complete picture, and factors specific to your situation may matter just as much.