延长缓冲期的三个杠杆

Financial runway — how many months your savings will last — is a function of exactly one ratio: your liquid savings divided by your monthly burn rate. That means there are only three ways to extend it: reduce spending, add income, or lower your cost of living by relocating (geoarbitrage). This tool lets you combine all three to see the compounding effect.

How the three levers interact

Runway (months) = savings ÷ (monthly expenses − monthly income). Because income is subtracted from expenses before dividing, even modest part-time or freelance income has an outsized effect on runway compared to the same dollar amount saved — reducing net burn from $3,000/month to $2,000/month (via $1,000/month of side income) extends a $30,000 fund from 10 months to 15 months, a 50% increase from a 33% reduction in net burn.

Why it matters

Most people instinctively reach for only one lever (usually cutting spending) when facing a shrinking runway, but small moves across all three levers often add up to more extended runway with less lifestyle sacrifice than an aggressive cut to just one. It's also the same underlying math used in the layoff runway and sabbatical calculators — this tool exists specifically to let you test combinations.

Common pitfalls

Side income and geoarbitrage savings are rarely available immediately — a new location or side gig takes time to set up, so runway calculations should account for a ramp-up period rather than assuming the full effect from day one. It's also easy to underestimate how "sticky" certain expenses are (a lease, a car payment, a mortgage) versus genuinely discretionary spending that can be cut quickly.