“Quit Your Job” Number Calculator

"How much do I need to quit my job" usually means one of two very different things, and mixing them up leads to bad decisions. The first is a runway question: can my current savings cover the gap between my side income and my expenses long enough to grow the side hustle into a full replacement? The second is a financial independence question: do I have enough invested that I never need active income again? Almost everyone quitting a job for a side hustle is answering the first question, not the second — the FI number is usually 10–20× bigger and not the right bar to clear.

Runway is the practical number: your safety buffer (savings) divided by your monthly income gap (expenses minus what the side hustle already earns) tells you how many months you can survive if the side hustle income stays flat. A six-month buffer is a common conservative target, long enough to weather a slow quarter or a client who churns without panicking back into a job search.

The moment your side income gap hits zero — your side hustle alone covers your monthly expenses — the runway calculation stops mattering, because you're no longer burning savings to sustain yourself. That's a more meaningful milestone than any specific savings number, and it's worth tracking explicitly rather than just watching your bank balance.

Until then, growing the side income and shrinking the gap does more for your timeline than saving harder — a $200/month increase in side income has the same effect on your runway as several thousand dollars of extra savings, but it's also the number that keeps growing after you quit, while savings only shrinks.

$3,200/month in expenses, $1,200/month already coming from the side hustle, and $15,000 saved: the monthly gap is $2,000, giving 7.5 months of runway at current savings — enough to clear a 6-month safety buffer target ($12,000) with room to spare. The full financial independence number at a 4% withdrawal rate, by contrast, is $960,000 ($3,200 × 12 ÷ 4%) — the number for never working again, not the number for quitting a job to focus on a side hustle. Confusing the two is why 'I need a million dollars to quit my job' feels impossible when the real, practical target might be $12,000–$20,000 in a safety buffer.