Most people know their gross salary and roughly what hits their bank account, but very few can explain what happens in between — and that gap is exactly where they overpay tax and undersave for retirement. This guide walks through the complete journey from a job offer's headline number to the dollars you can actually spend, using 2026 US tax structure as the working example (with notes for other systems). By the end you'll be able to estimate take-home pay, compare two job offers properly, and understand why a raise sometimes feels smaller than it should.