Pay yourself like a startup: an engineer's approach to personal runway

Personal runway is the number of months you could cover your expenses with zero income, and most engineers who'd never ship a system without monitoring it have never calculated their own. It's one number, it takes ten minutes to compute, and it changes how every other financial decision looks.

How do you calculate your actual personal runway?

Three steps:

1. Add up your liquid savings — checking, savings, anything sellable within a month without a penalty.
2. Divide that by your real monthly burn — not your budget, but your actual average spend over the last three months of bank statements.
3. Compare the result to a threshold that fits your risk: six months is a common comfort level, adjusted up if your income is hard to replace or you're carrying extra risk (a mortgage, dependents, a visa tied to one employer).

Why do engineers underestimate how thin their runway is?

A high salary creates an illusion of safety that a bank balance doesn't always back up — lifestyle costs tend to rise with income at roughly the same rate, so take-home pay going up doesn't automatically mean runway going up. The only way to know is to actually run the numbers, the same way you wouldn't trust a system's uptime without checking a dashboard.

How should you treat savings like a startup treats fundraising?

Startups don't wait until they're down to one month of runway to think about the next raise — they start planning at six months out. Apply the same lead time personally: pick a runway floor below which you start actively cutting cost or building income before you hit it, not after. The goal isn't hoarding cash indefinitely; it's never making a career decision purely because you're out of room to say no.