What this calculator does
This calculator answers the insolvency question: how long can you keep spending the way you do before the accounts run dry? It is the bridge between income and lifestyle.
The math
Monthly surplus or deficit = income − expenses. Months until broke = savings ÷ deficit. Months to 3-month emergency fund = (3 × expenses − savings) ÷ surplus.
Worked example
With $3,500 income, $3,900 expenses, and $1,200 savings, you burn $400 per month and hit zero in 3 months. With $4,000 income and $3,000 expenses, you build a 3-month emergency fund in about 2 months.
Why this matters
When money is tight, the right arithmetic can protect your housing, food, and transportation. This tool gives you a fast triage number so you can make the least-damaging choice.
Methodology and transparency
This page publishes the exact formula used to compute the result, so you can verify it in a spreadsheet or check the assumptions against your own situation. The worked example uses the tool default inputs; change any number and the result updates live in your browser. No data is sent or stored.
Common questions
What does insolvent mean here?
It means your expenses exceed your income. You are not out of money yet if you have savings, but you are on a countdown.
Should I include retirement contributions?
Include them as expenses if you would stop them in an emergency. Otherwise leave them out to see the core lifestyle gap.
What if the runway is under 6 months?
Treat it as an emergency. Cut non-survival spending until income covers expenses.